Memory cell, capacitor memory structure and method thereof

Abstract

According to various aspects, a memory cell is provided that includes a first electrode, a second electrode, and a memory structure disposed between the first electrode and the second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor, wherein at least one of the first electrode and the second electrode includes a first electrode layer including a first material having a first microstructure, a functional layer in direct contact with the first electrode layer, and a second electrode layer in direct contact with the functional layer, the second electrode layer including a second material having a second microstructure different from the first microstructure.

Description

Technical Field

[0001] Various aspects relate to a memory cell and a method thereof, such as a method for processing a memory cell. Background Technology

[0002] In general, various computer memory technologies have been developed in the semiconductor industry. The basic building blocks of computer memory can be referred to as memory cells. A memory cell can be an electronic circuit configured to (e.g., bitwise) store at least one piece of information. As an example, a memory cell can have at least two memory states, representing, for example, logic "1" and logic "0". Typically, information can be retained (stored) in the memory cell until, for example, the memory state of the memory cell is modified in a controlled manner. The information stored in the memory cell can be obtained by determining which memory state the memory cell is in. Currently, various types of memory cells can be used to store data. For example, the type of memory cell can include a thin film of ferroelectric material whose polarization state can be changed in a controlled manner, thereby storing data in the memory cell, for example, in a non-volatile manner. Memory cells can be integrated with one or more logic circuits on, for example, a wafer or chip. Attached Figure Description

[0003] In the accompanying drawings, the same reference numerals generally denote the same parts in different views. The drawings are not necessarily drawn to scale, but rather the emphasis is generally placed on illustrating the principles of the invention. In the following description, various aspects of the invention are described with reference to the following drawings, wherein:

[0004] Figure 1 The structure of a field-effect transistor is schematically shown according to various aspects;

[0005] Figure 2 The equivalent circuit diagram of the memory cell is schematically shown according to various aspects;

[0006] Figures 3A to 3E Each schematically illustrates a memory cell according to various aspects;

[0007] Figure 4A The memory capacitors are schematically shown according to various aspects;

[0008] Figure 4B The memory cells are schematically shown according to various aspects;

[0009] Figures 5A to 5D Each electrode is schematically shown according to its respective aspect;

[0010] Figure 6A and Figure 6B Each schematically illustrates a portion of the memory capacitor according to various aspects;

[0011] Figure 7 A schematic flowchart illustrating a method for forming a memory capacitor according to various aspects is provided; and

[0012] Figure 8 A schematic flowchart illustrating a method for forming a memory capacitor according to various aspects is shown. Detailed Implementation

[0013] The following detailed description refers to the accompanying drawings, which illustrate by way of illustration specific details and aspects in which the invention may be practiced. These aspects are described in sufficient detail to enable those skilled in the art to practice the invention. Other aspects may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The aspects are not necessarily mutually exclusive, as some aspects may be combined with one or more other aspects to form new aspects. Combination methods describe the aspects, and combination devices (e.g., memory cells or memory capacitors) describe the aspects. However, it is understood that the aspects described by the combination methods can be similarly applied to devices, and vice versa.

[0014] The terms “at least one” and “one or more” can be understood to include any integer greater than or equal to one, i.e., one, two, three, four, [...], etc. The terms “multiple” or “multiple” can be understood to include any integer greater than or equal to two, i.e., two, three, four, five, [...], etc.

[0015] Regarding a group of elements, the phrase "at least one" may be used herein to mean at least one element from a group consisting of these elements. For example, regarding a group of elements, the phrase "at least one" may be used herein to mean one of the listed elements, one of the multiple listed elements, multiple individual listed elements, or a multiple of the multiple listed elements.

[0016] In the semiconductor industry, the integration of non-volatile memory technology can be used in system-on-chip (SoC) products such as microcontrollers (MCUs). Depending on the aspect, non-volatile memory can be integrated near the processor core of a processor. As another example, one or more non-volatile memories can be used as part of a high-capacity memory device. In some aspects, non-volatile memory technology can be based on at least one field-effect transistor (FET) structure. In some aspects, the memory cell can include a field-effect transistor structure and a capacitive memory structure (also referred to herein as a memory capacitor) coupled to the gate electrode of the field-effect transistor structure. The amount of charge stored in the capacitive memory structure affects one or more threshold voltages of the field-effect transistor structure. One or more threshold voltages of the field-effect transistor structure define the memory state in which the memory cell is located. In some aspects, the capacitive memory structure can be a ferroelectric capacitor structure (FeCAP) coupled to the gate electrode of the field-effect transistor structure to provide a ferroelectric field-effect transistor (FeFET) structure. Because ferroelectric materials can have at least two stable polarization states, they can be used to non-volatilely switch the threshold voltage of the field-effect transistor; therefore, ferroelectric materials can be used to transform a field-effect transistor into a memory structure based on a non-volatile field-effect transistor. Ferroelectric materials can transform ferroelectric capacitor structures into memory structures based on non-volatile capacitors, for example, by controlling the amount of charge stored in the capacitor structure. In other aspects, non-volatile memory technology can be based on at least one capacitive memory structure. The capacitive memory structure can be or may include a ferroelectric capacitor structure. The amount of charge stored in the capacitive memory structure can be read out by suitable electronic readout circuitry, for example, by a charge-to-voltage converter, by determining the switching current of the capacitive memory structure.

[0017] A memory cell based on a ferroelectric field-effect transistor (FeFET) may include two elements—a transistor and a ferroelectric capacitor (FeCAP). Improving FeFET performance may include one or more modifications to the FeCAP layer stack. The FeCAP layer stack may include different materials suitable for increasing ferroelectricity and reducing parasitic effects. In some aspects, leakage in the FeCAP layer stack can be reduced by modifying the electrode materials and the electrode crystal structure to induce different crystal behaviors in the ferroelectric material.

[0018] Depending on the aspects, the memory layer of a memory cell (e.g., the memory layer of a capacitor memory structure) may include or be made of a polarizing material, such as a spontaneously polarizing material (e.g., antiferroelectric and / or ferroelectric materials, as an example). Antiferroelectric materials may exhibit hysteresis in (voltage-dependent) polarization; however, in the absence of a voltage drop across the antiferroelectric material, there is no or substantially no residual polarization. Ferroelectric materials may exhibit hysteresis in (voltage-dependent) polarization; however, in the absence of a voltage drop across the ferroelectric material, residual or substantial residual polarization still exists. Spontaneous polarization (e.g., residual or non-residual spontaneous polarization) can be evaluated by analyzing one or more hysteresis measurements (e.g., hysteresis curves), such as in a graph of polarization P versus electric field E, where the material is polarized in opposite directions. The polarization capability of a material (dielectric polarization, spontaneous polarization, and remanence of polarization) can be analyzed using capacitance spectroscopy, for example, by static (CV) and / or time-resolved measurements or by polarization-voltage (PV) or positive-up-negative-down (PUND) measurements. In this specification, various aspects are described with respect to exemplary configurations of memory layers (e.g., memory layers in capacitor memory structures) as memory cells, such as remanent polarization layers comprising ferroelectric materials. However, it should be understood that the aspects described herein are generally applicable to spontaneously polarized layers of memory layers as memory cells.

[0019] The term "spontaneously polarized" or "spontaneously polarized" may be used herein, for example, with respect to the polarization capability of materials beyond dielectric polarization. "Spontaneously polarized" (or "spontaneously polarized") materials may be or may include spontaneously polarized materials exhibiting remanence, such as ferroelectric materials, and / or spontaneously polarized materials not exhibiting remanence, such as antiferroelectric materials. The coercivity of a material can be a measure of the strength of the reverse polarization electric field that may be required to remove remanence. Depending on the aspects, the coercive electric field E C (Also known as a coercive field) can be or represents the electric field required to depolarize the remaining polarization layer.

[0020] Depending on various aspects, ferroelectric materials can be examples of materials used in spontaneously polarized layers (e.g., in remanent polarized layers). Depending on various aspects, ferroelectric layers can be examples of spontaneously polarized layers (e.g., remanent polarized layers).

[0021] In some aspects, the remanent polarization layer, remanent polarization structure, remanent polarization memory cell, and remanent polarization portion (by way of example only) may include a remanently polarized material (i.e., exhibiting remanence with spontaneous polarization), such as a ferroelectric material. In other aspects, the remanent polarization layer, remanent polarization structure, remanent polarization memory cell, and remanent polarization portion (by way of example only) may include a material that spontaneously polarizes and does not exhibit remanence under additional conditions of taking measures to generate an internal electric field within the antiferroelectric material, such as an antiferroelectric material. The internal electric field within the antiferroelectric material can be induced by various strategies (e.g., applied, generated, maintained, by way of example only): for example, by implementing a floating node rechargeable to a voltage other than zero volts, and / or by implementing a charge storage layer, and / or by using a doped layer, and / or by using an electrode layer adapted to the electronic work function to generate the internal electric field, by way of example only.

[0022] Figure 1 The schematic function of a field-effect transistor structure 100 is illustrated according to various aspects. The field-effect transistor structure 100 may include a gate structure 108, wherein the gate structure 108 may include a gate isolation 104 and a gate electrode 106. The gate structure 108 is exemplarily shown as a planar gate stack; however, it will be understood that... Figure 1 The planar configuration shown is exemplary, and other field-effect transistor designs may include gate structures 108 with non-planar shapes, such as, for example, trench gate transistor designs, vertical field-effect transistor designs, or as shown in the example. Figure 3D and Figure 3E Other designs are illustrated exemplarily. Gate structure 108 may define a channel region 102, for example, disposed in a semiconductor portion (e.g., in a semiconductor layer, in a semiconductor die, etc.). Gate structure 108 may allow control over the electrical behavior of channel region 102. For example, gate structure 108 may be used, for example, to control (e.g., allow or block) current in channel region 102. In some aspects, gate structure 108 may, for example, allow control (e.g., allow or block) the source / drain current I from the first source / drain region of field-effect transistor structure 100 to the second source / drain region of field-effect transistor structure 100. SD (The source / drain is located in or adjacent to the channel but not in the channel) Figure 1 (As shown in the diagram). The channel region 102 and the source / drain regions may be formed, for example, by doping one or more semiconductor materials or by using intrinsically doped semiconductor materials, within and / or above the layer. In some aspects, the gate structure 108 may control (e.g., increase or decrease) the resistance R of the channel region 102, and thus control the amount of current that may flow through the channel region 102. Regarding the operation of the field-effect transistor structure 100, a voltage (illustratively, a potential) may be provided (e.g., supplied to) the gate electrode 106 to control the current I in the channel region 102. SDThe current I in channel region 102 SD Caused by the voltage supplied via the source / drain regions.

[0023] Gate electrode 106 may include a conductive material, such as polysilicon, aluminum, etc. In some aspects, gate electrode 106 may include any suitable conductive material, such as a metal, a metal alloy, or a degenerate semiconductor (in other words, a semiconductor material with such a high doping level that it functions like a metal rather than a semiconductor). Depending on the aspect, gate electrode 106 may include one or more conductive portions, layers, etc. Gate electrode 106 may include, for example, one or more metal layers (also referred to as a metal gate), one or more polysilicon layers (also referred to as a polysilicon gate), etc. The metal gate may include, for example, at least one work function-adaptive metal layer disposed above gate isolation 104 and an additional metal layer disposed above the work function-adaptive metal layer. The polysilicon gate may be, for example, p-type doped or n-type doped.

[0024] Depending on various aspects, gate isolation 104 may be configured to provide electrical isolation between gate electrode 106 and channel region 102 and further influence channel region 102 through the electric field generated by gate electrode 106. As described in more detail below, gate isolation 104 may include one or more electrically insulating portions, layers, etc.

[0025] Some designs for the gate isolation 104 may include at least two layers of different materials, such as a first gate isolation layer 104-1 (e.g., a first dielectric layer comprising a first dielectric material) and a second gate isolation layer 104-2 (e.g., a second dielectric layer comprising a second dielectric material different from the first dielectric material). The second gate isolation layer 104-2 may be disposed above the first gate isolation layer 104-1. Illustratively, the first gate isolation layer 104-1 may be configured to be closer to the channel region 102 of the field-effect transistor structure 100 than the second gate isolation layer 104-2. The first gate isolation layer 104-1 may be disposed directly above the channel region 102 and may provide an interface for forming the second gate isolation layer 104-2. In some aspects, the first gate isolation layer 104-1 may be referred to as a buffer layer.

[0026] like Figure 1 The equivalent circuit shown in the figure shows the first capacitor C. FET This can be associated with field-effect transistor structure 100. Illustratively, channel region 102, gate isolation 104, and gate electrode 106 may have an associated capacitance C. FETThe capacitance originates from strongly or weakly conductive regions (channel region 102 and gate electrode 106) separated from each other by gate isolation 104. Further illustratively, channel region 102 can be considered as the first capacitor electrode, gate electrode 106 as the second capacitor electrode, and gate isolation 104 as the dielectric between the two capacitor electrodes. The capacitance C of the field-effect transistor structure 100... FET One or more operating characteristics of the field-effect transistor structure 100 may be defined. The configuration of the field-effect transistor structure 100 (e.g., of the gate isolation 104) may be adjusted according to the desired behavior of the field-effect transistor structure 100 during operation or the application (e.g., according to the desired capacitance), as described in more detail below.

[0027] Typically, the capacitance C of a planar capacitor structure can be expressed as,

[0028] C = ,

[0029] Where ε₀ is the relative permittivity of vacuum, A is the effective area of ​​the capacitor, d is the distance between the two capacitor electrodes, and ε r It is the relative permittivity of the dielectric material disposed between the two capacitor electrodes, assuming that the entire gap between the two capacitor electrodes is filled with dielectric material. It should be noted that the capacitance of non-planar capacitor structures or improved variants of planar capacitor structures can be calculated based on equations known in the art.

[0030] According to various embodiments, memory cells (e.g., such as those provided by coupling the gate of a field-effect transistor structure to a capacitor memory structure, or by integrating the memory structure into the gate structure of a field-effect transistor structure) can be provided. Figure 2 and Figures 3A to 3E (As shown).

[0031] The impact of capacitance in a field-effect transistor structure on the performance of memory cells, including those in a capacitor memory structure, is described in further detail below.

[0032] Figure 2 The equivalent circuit of a memory cell 200, including a field-effect transistor (FET) structure 200a (configured, for example, as described herein with respect to FET structure 100) and a capacitor memory structure 200b, is shown according to various aspects. The FET structure 200a may have a first capacitor C associated with it. FET Furthermore, the capacitor memory structure 200b may have a second capacitor C associated with it. CAPThe field-effect transistor structure 200a and the capacitor memory structure 200b can be coupled to each other (e.g., electrically connected) to provide a capacitive voltage divider. The channel or body node of the field-effect transistor structure 200a can be provided or connected to a first node 222, the electrodes of the capacitor memory structure 200b can be provided or connected to a second node 226, and intermediate conductive portions (electrodes, layers, etc.) can be provided or connected to a floating intermediate node 224. Examples will follow regarding... Figures 3A to 3E An exemplary implementation of such a connection structure is described in more detail.

[0033] The capacitor voltage divider formed by the field-effect transistor structure 200a and the capacitor memory structure 200b allows adjustment of the capacitance C of the corresponding capacitor. FET C CAP This allows for efficient programming of the capacitor memory structure 200b. With the voltage distribution across the field-effect transistor structure 200a and the capacitor memory structure 200b adjusted such that a greater application of the gate voltage across the memory layer of the capacitor memory structure 200b (e.g., across the residual polarization layer, such as a ferroelectric layer) compared to the gate isolation of the field-effect transistor structure 200a, the total gate voltage required to switch the memory cell 200 from one memory state to another (e.g., from a high threshold voltage state to a low threshold voltage state, as described below) can be reduced. Therefore, the total write voltage (illustratively applied via nodes 222, 226 to which the field-effect transistor structure 200a and the capacitor memory structure 200b are connected) can be reduced by adjusting the capacitor voltage divider. The voltage distribution can be determined by calculation using a voltage divider of series-connected capacitors.

[0034] That is, in the field-effect transistor structure 200a, the capacitance C FET When adjusted (e.g., by providing suitable gate isolation), a predetermined portion of the voltage applied to the series connection can decrease across the capacitor memory structure 200b. Therefore, if desired, the electric field generated by the gate isolation of the field-effect transistor structure 200a below the capacitor memory structure 200b can be reduced. This results in reduced interfacial field stress, which may lead to reduced interfacial wear, for example, attributable to charge injection. Thus, the reduced electric field generated across the gate isolation can lead to improved durability characteristics of the memory cell 200, i.e., an increased possible polarization reversal amount until the memory cell 200 may lose or alter its memory characteristics.

[0035] In some aspects, the memory layer of the capacitor memory structure 200b can be a residual polarization layer. This is achieved by increasing the capacitance C of the field-effect transistor structure 200a. FET (For example, by providing gate isolation comprising a relatively thick material layer with a high dielectric constant), the depolarization field E of the residual polarization layer can be reduced.Dep The depolarization field can be represented by the following set of equations, where the subscript "FET" refers to the capacitor provided by the field-effect transistor structure 200a, and the subscript "CAP" refers to the capacitor provided by the capacitor memory structure 200b, as described herein:

[0036] 0,

[0037] D = = ,

[0038] .

[0039] Depolarization field E Dep This may be detrimental to data retention because, depending on its magnitude, it could depolarize the remaining polarization layer. However, this can be mitigated by increasing the capacitance ratio C. FET / C CAP To reduce the magnitude. Therefore, in the field-effect transistor structure 200a, the capacitance C FET With the increase, the depolarization field decreases. This further improves the data retention of memory cell 200.

[0040] In the first approximation, the voltage V that drops across the memory structure capacitor is... CAP It can be estimated using the following formula:

[0041] ,

[0042] Among them, V 226 This indicates that the capacitance is applied to the top node 226 (e.g., to the top electrode of the capacitor memory structure 200b, for example assuming that node 222 associated with the body of the field-effect transistor structure 200a is connected to the base potential, such as ground or 0V), and the capacitance is generally defined as described above. A suitable parameter for influencing the voltage drop across the capacitor memory structure 200b (e.g., across a ferroelectric capacitor) can be represented by the area ratio between the capacitor memory structure 200b and the field-effect transistor structure 200a and / or by the relative permittivity of the field-effect transistor structure 200a (e.g., the gate isolation of the field-effect transistor structure 200a). In some aspects, the capacitance C of the field-effect transistor structure 200a is adjusted. FET Adjusting the gate voltage divider allows the thickness of the layers (e.g., memory layers, such as spontaneously polarized layers, such as residual polarized layers) of the capacitor memory structure 200b to be kept within a predetermined range.

[0043] Figures 3A to 3EThe possible implementations of corresponding memory cells 300a, 300b, 300c, 300d, and 300e are schematically shown. These memory cells 300a, 300b, 300c, 300d, and 300e can be configured such that the field-effect transistor structure 302a of the corresponding memory cells 300a, 300b, 300c, 300d, and 300e is connected to the capacitor memory structure 302b to form a capacitor voltage divider C. FET / C CAP For reference Figure 2 The memory cell 200 described herein. Each of the described memory cells 300a, 300b, 300c, 300d, and 300e may include a field-effect transistor structure 302a, which includes a channel 304 (also referred to herein as channel region 304), a gate isolation 306, and a gate electrode 308. The channel 304, gate isolation 306, and gate electrode 308 may be configured as described above, for example, with reference to the channel 102, gate isolation 104, and gate electrode 106 of the field-effect transistor structure 100. In some aspects, the gate isolation 306 may include a first gate isolation layer 306a and a second gate isolation layer 306b. In other aspects, the gate isolation 306 may include a single gate isolation layer, thus omitting one of the two gate isolation layers 306a and 306b. The gate isolation 306 may extend from the channel region 304 to the gate electrode 308.

[0044] In some aspects, the first gate isolation layer 306a may be in direct physical contact with the channel region 304. The second gate isolation layer 306b may be in direct physical contact with the first gate isolation layer 306a and the gate electrode 308 of the field-effect transistor structure 302a.

[0045] Each of the described memory cells 300a, 300b, 300c, 300d, and 300e may include a capacitive memory structure 302b electrically connected (in other words, electrically coupled) to a field-effect transistor structure 302a. The capacitive memory structure 302b may include any type of planar or non-planar design having at least a first electrode 322, a second electrode 326, and at least one memory structure 324 disposed between the first electrode 322 and the second electrode 326, for example, to provide memory functionality. The memory structure 324 may be or may include one or more memory layers, such as one or more residual polarization layers. However, the memory structure 324 may include memory materials or other implementations of memory structures, such as an antiferroelectric layer coupled to a charge storage layer (e.g., directly disposed thereon). The charge storage layer may include any material suitable for storing charge (e.g., by trapping).

[0046] As referenced above Figure 2As described in memory cell 200, for example, by connecting one electrode (e.g., first electrode 322) of capacitor memory structure 302b to gate electrode 308 of field-effect transistor structure 302a, field-effect transistor structure 302a can be connected to capacitor memory structure 302b to form capacitive voltage divider C. FET / C CAP For example, Figure 3A As shown. The conductive connection between the capacitor memory structure 302b and the field-effect transistor structure 302a (e.g., the first electrode 322 and the gate electrode 308) can provide a series capacitive connection between the capacitor formed by the capacitor memory structure 302b and the field-effect transistor structure 302a. In a planar configuration, the first electrode 322 of the capacitor memory structure 302b can be a first capacitor electrode, the second electrode 326 can be a second capacitor electrode, and at least one memory structure 324 can be a dielectric between the first electrode and the second capacitor electrode.

[0047] In some aspects, the gate electrode 308 of the field-effect transistor structure 302a may be electrically connected to the first electrode 322 of the capacitor memory structure 302b via a conductive (e.g., ohmic) connection 310, such as... Figure 3A As shown. In some aspects, the first electrode 322 of the capacitor memory structure 302b may be in direct physical contact with the gate electrode 308 of the field-effect transistor structure 302a.

[0048] In some aspects, the capacitor memory structure 302b and the field-effect transistor structure 302a may share a common electrode that serves as the gate electrode of the field-effect transistor structure 302a and the electrode of the capacitor memory structure 302b, such as Figure 3B As shown.

[0049] In some aspects, the conductive (e.g., ohmic) connection 310 between the field-effect transistor structure 302a and the capacitor memory structure 302b may be provided by one or more metallization structures disposed above the field-effect transistor structure 302a, such as... Figure 3C As shown.

[0050] At least one memory structure 324 may comprise any type of remanent polarization and / or spontaneous polarization material, such as ferroelectric materials, antiferroelectric materials, antiferroelectric-like materials, etc. At least one memory structure 324 may be a memory layer of a capacitor memory structure 302b to store information, for example, via at least two remanent polarization states of at least one memory structure 324. An electric field may be provided between the first electrode 322 and the second electrode 326 (e.g., the potential difference between a first node and a second node associated with the first electrode 322 and the second electrode 326, respectively, as per [reference to...]). Figure 2The described method is used to program the capacitor memory structure 302b (illustratively, in which information is stored) to set or change the residual polarization state of at least one memory structure 324. As an example, a voltage may be provided between the top electrode 326 and the body region of the field-effect transistor structure 302a.

[0051] It is understood that memory structure 324 is merely an example of a possible memory layer of capacitor memory structure 302b, and any other memory layer whose state can be altered by an electric field provided across capacitor memory structure 302b may be used. In some aspects, the material of memory structure 324 may include hafnium and / or zirconium.

[0052] Typically, when a material layer maintains its polarization when the applied electric field (E) is reduced to zero, remanent polarization (also known as magnetism retention or remanence) can exist in the material layer. Therefore, a specific value of the polarization (P) of the material layer can be detected. Illustratively, the remaining polarization in a material when the electric field is reduced to zero can be called remanent polarization. Therefore, the remanence of a material can be a measure of the remanent polarization in the material when the applied electric field is removed. Generally, ferroelectricity and antiferroelectricity can be concepts used to describe the remanent polarization of a material, similar to ferromagnetism and antiferromagnetism used to describe the remanence in magnetic materials.

[0053] Depending on the aspects, ferroelectric materials can be used as part of a capacitive memory structure of a memory cell (e.g., as part of capacitive memory structure 302b of memory cells 300a, 300b, 300c, 300d, 300e, or as part of capacitive memory structure 200b of memory cell 200). Ferroelectric materials can be examples of materials used for the residual polarization layer (e.g., of memory structure 324). Illustratively, ferroelectric materials can be used to store data in an integrated circuit in a non-volatile manner. The term "ferroelectric" may be used herein, for example, to describe materials exhibiting a hysteresis charge-voltage relationship (QV). Ferroelectric materials can be or may include at least one of the following: hafnium oxide (ferroelectric hafnium oxide, HfO2), zirconium oxide (ferroelectric zirconium oxide, ZrO2), and (ferroelectric) mixtures of hafnium oxide and zirconium oxide. Ferroelectric hafnium oxide may include any form of hafnium oxide capable of exhibiting ferroelectric properties. Ferroelectric zirconium oxide may include any form of zirconium oxide capable of exhibiting ferroelectric properties. This may include, for example, solid solutions of hafnium oxide, zirconium oxide, hafnium oxide, and zirconium oxide (e.g., but not limited to 1:1 mixtures) or doped or substituted hafnium oxide and / or zirconium oxide with one or more of the following elements (not an exhaustive list): silicon, aluminum, gadolinium, yttrium, lanthanum, strontium, zirconium, any rare earth element, or any other dopant (dopant) suitable for providing or maintaining ferroelectricity in hafnium oxide or zirconium oxide. Ferroelectric materials may be doped at concentrations of about 2 mol% to about 6 mol%, by way of example only.

[0054] Depending on various aspects, a memory cell (e.g., memory cells 200, 300a, 300b, 300c, 300d, 300e) may have at least two distinct states associated with it, such as two distinct electrical conductivities or two distinct amounts of stored charge that can be determined to identify which of the at least two distinct states the memory cell is in. Depending on various aspects, the memory state of the memory cell may be a "programming state" or an "erase state." For example, a programming state may be a conductive state or a state with a positive stored charge (e.g., associated with logic "1"), and an erase state may be a non-conductive state or a state with a negative stored charge (e.g., associated with logic "0"). However, the definitions of programming and erase states can be arbitrarily chosen.

[0055] Depending on various aspects, the residual polarization of the residual polarization layer can define the memory state of the memory cell. The polarization state of the residual polarization layer can be switched by a capacitor memory structure. The polarization state of the residual polarization layer can also be read out by the capacitor memory structure. Depending on various aspects, when the residual polarization layer is in a first polarization state, the memory cell can be in a first memory state, and when the residual polarization layer is in a second polarization state (e.g., opposite to the first polarization state), the memory cell can be in a second memory state. As an example, the polarization state of the residual polarization layer can determine the amount of charge stored in the capacitor memory structure. The amount of charge stored in the capacitor memory structure can be used to define the memory state of the memory cell. The threshold voltage of the field-effect transistor structure (e.g., field-effect transistor structure 200a, field-effect transistor structure 302a) can be a function of the amount of charge and / or the charge polarity stored in the capacitor memory structure, for example, depending on the polarization state of the residual polarization layer. The first threshold voltage, for example, the high threshold voltage V. H-th This can be associated with a first polarization state (e.g., with a first quantity and / or polarity of stored charge), and a second threshold voltage, such as a low threshold voltage V. L-th This can be associated with a second polarization state (e.g., with a second quantity and / or polarity of stored charge). Illustratively, a first memory state can be associated with a first threshold voltage, and a second memory state can be associated with a second threshold voltage.

[0056] Depending on various aspects, the second gate isolation layer 306b of the gate isolation 306 of the field-effect transistor structure 302a may be a layer different from the memory layer of the capacitor memory structure 302b (e.g., different from the memory structure 324), for example, differing in at least one aspect, such as the type of material or the remanent polarization characteristics of the material. For example, the material of the second gate isolation layer 306b may not have remanent polarization characteristics, such as not having ferroelectric properties.

[0057] Depending on the aspect, the semiconductor portion (exemplarily, where the channel region 304 may be formed) may be made of silicon or may include silicon. However, various other types of semiconductor materials, such as germanium, group III to V (e.g., SiC), or other types, including, for example, carbon nanotubes, organic materials (e.g., organic polymers), may be used in a similar manner. In various aspects, the semiconductor portion may be a silicon wafer (e.g., p-type doped or n-type doped). In other aspects, the semiconductor portion may be a silicon-on-insulator (SOI) wafer. In other aspects, the semiconductor portion may be provided by a semiconductor structure disposed on a carrier, such as one or more semiconductor fins, one or more semiconductor nanosheets, one or more semiconductor nanowires, etc.

[0058] Figure 3C An exemplary integration scheme of memory cell 300c according to various aspects is illustrated schematically, wherein a metallization structure is provided to electrically connect field-effect transistor structure 302a to capacitor memory structure 302b. It is understood that the metallization structure may include multiple metallization structures, such as multiple single-level or multi-level contact structures.

[0059] The metallization structure can be configured to electrically connect the gate electrode 308 of the field-effect transistor structure 302a to the first electrode 322 of the capacitor memory structure 302b. For example, the metallization structure may include a contact metallization. The contact metallization may be at least partially disposed between the field-effect transistor structure 302a and the capacitor memory structure 302b. As another example, the metallization structure may include a contact metallization and a single-level or multi-level metallization disposed above the contact metallization. In this case, both the contact metallization and at least one single-level or multi-level metallization may be disposed between the field-effect transistor structure 302a and the capacitor memory structure 302b.

[0060] The metallization structure may include a gate contact structure 344 (also referred to as a gate contact). The gate contact structure 344 may be embedded in an insulating layer 342 (e.g., may be laterally surrounded by the insulating layer 342). The insulating layer 342 may include a dielectric material having a thickness, for example, in the range of about 10 nm to about 100 nm (e.g., a thickness of 40 nm), such as silicon oxide (SiO2) or silicon nitride (SiN). xIn some aspects, the insulating layer 342 may include multiple insulating layers, for example, each comprising the same material or different materials. The gate contact structure 344 may include at least one metal layer, for example, comprising tungsten (W), cobalt (Co), etc. The gate contact structure 344 may be in direct physical contact with the gate electrode 308 of the field-effect transistor structure 302a. The gate contact structure 344 may be in direct physical contact with the first electrode 322 of the capacitor memory structure 302b. Depending on various aspects, the electrical connection between the first electrode 322 of the capacitor memory structure 302b and the gate electrode 308 of the field-effect transistor structure 302a may be formed by the gate contact structure 344.

[0061] An additional metallization structure may be formed above the capacitor memory structure 302b (e.g., in...). Figure 3D and Figure 3E (As shown in the figure). Additional metallization structures may include memory contact structures (also referred to as memory contacts). The memory contact structures may embed additional (e.g., a second) insulating layers (e.g., may be laterally surrounded by additional insulating layers).

[0062] Figure 3D and Figure 3E Possible non-planar structures for memory cells 300d and 300e are shown, for example, for field-effect transistor structure 302a (e.g., for the memory transistor described above).

[0063] exist Figure 3D In the integrated scheme shown, at least the field-effect transistor structure 302a of the memory cell 300d can be configured as a fin field-effect transistor (FinFET). The semiconductor portion having the channel region 304 can have the shape of a vertical fin, wherein the gate isolation 306 and the gate electrode 308 can at least partially surround the fin.

[0064] exist Figure 3E In the integrated scheme shown, at least the field-effect transistor structure 302a of the memory cell 300e can be configured as a nanosheet or nanowire field-effect transistor. One or more semiconductor portions having a channel region 304 can each have a nanosheet or nanowire shape. The gate isolation 306 and the gate electrode 308 can at least partially surround the respective nanosheet or nanowire.

[0065] When the layer thickness is reduced to below 2 nm, or at least when the reduction in film thickness leads to an unacceptably high crystallization temperature that destabilizes the ferroelectric phase in HfO2, the ferroelectric properties of ferroelectric HfO2 may disappear. Therefore, depending on various aspects, the layer thickness of the ferroelectric HfO2 layer used in capacitor memory structures can be selected to be greater than or equal to 2 nm. For transistor platforms, for example in… Figure 3D and Figure 3EAs exemplarily shown, it may be advantageous to arrange a ferroelectric HfO2 layer on top of a field-effect transistor structure so that the ferroelectric HfO2 layer can achieve the desired layer thickness in these processing platforms.

[0066] Various aspects of the present invention may relate to adjusting one or more electrodes of a memory capacitor to provide improved electrical characteristics and / or improved memory characteristics of the memory capacitor. In some aspects, the electrodes of the memory capacitor may be configured to influence the characteristics of the memory structure formed thereon, such as influencing the growth of a residual polarization layer formed on the electrodes. The characteristics of the electrodes are tunable to obtain desired structural characteristics of the memory structure (e.g., the desired average grain size of the residual polarization material of the memory structure). In some aspects, the electrodes of the memory capacitor may be configured to reduce or prevent oxygen migration away from the memory structure, which would otherwise lead to degradation or loss of memory characteristics. In some aspects, the electrodes of the memory capacitor may be configured to reduce or prevent leakage current from the memory capacitor, thereby improving the data retention capability of the memory capacitor.

[0067] Figure 4A The memory capacitor 400b is illustrated schematically according to various aspects. In these aspects, the memory capacitor 400b can be configured as shown regarding... Figures 2 to 3E The described capacitor memory structures 200b and 302b may include at least one adapter electrode, as further described below. The memory capacitor 400b may include a first electrode 402 (bottom electrode), a second electrode 404 (top electrode), and a memory structure 406 disposed between the first electrode 402 and the second electrode 404 (e.g., as described with respect to the first electrode 322, the second electrode 326, and the memory structure 324). The first electrode 402, the second electrode 404, and the memory structure 406 may form the memory capacitor 400b. Illustratively, the first electrode 402, the second electrode 404, and the memory structure 406 may be disposed relative to each other such that data (e.g., logic "0" or logic "1") can be stored in the memory capacitor 400b, data can be written by the state of the first electrode 402 and the second electrode 404 acting on the memory structure 406, and data can be read out by the first electrode 402 and the second electrode 404 depending on the state of the memory structure 406. In some aspects, memory structure 406 may be in direct physical contact with first electrode 402 and second electrode 404. Illustratively, a first (shared) interface region may exist between memory structure 406 and first electrode 402, and a second (shared) interface region may exist between memory structure 406 and second electrode 404.

[0068] In some aspects, the memory structure may include one or more layers, and at least one layer may include an oxygen-containing material (e.g., an oxide). In some aspects, memory structure 406 may include one or more residual polarization layers. Memory structure 406 may allow data storage based on one or more layers comprising one or more suitable materials or suitable combinations of materials with (residual) polarization. In other aspects, memory structure 406 may include one or more charge storage layers. Memory structure 406 may allow data storage based on charging one or more charge storage layers comprising one or more suitable materials or suitable combinations of materials (e.g., permanently). In other aspects, memory structure 406 may include one or more charge storage layers and one or more polarization layers, such as one or more spontaneously polarized layers (e.g., one or more antiferroelectric layers). Memory structure 406 may allow data storage based on charging one or more charge storage layers assisted by one or more polarization layers (e.g., permanently). In some aspects, memory structure 406 may have a thickness in the range of about 2 nm to about 50 nm (e.g., about 5 nm to about 30 nm, or about 10 nm to about 20 nm).

[0069] At least one of the first electrode 402 and the second electrode 404 may be adapted to provide improved electrical characteristics and / or improved memory characteristics, as shown below for example regarding Figures 5A to 5D Further detailed description.

[0070] Figure 4B The memory cell 400 is illustrated schematically according to various aspects. The memory cell 400 can be configured as shown in relation to... Figure 2 and about Figures 3A to 3E The memory cells described are 200, 300a, 300b, 300c, 300d, and 300e.

[0071] In various aspects, the memory cell 400 may include a field-effect transistor structure 400a coupled to each other and a memory capacitor 400b. The field-effect transistor structure 400a may be configured as shown regarding Figures 1 to 3E The field-effect transistor structures 100, 200a, and 302a are described. Field-effect transistor structure 400a and memory capacitor 400b can be coupled to each other to form a capacitive voltage divider (see example...). Figure 2 The field-effect transistor structure 400a may include a gate structure 410 coupled to the memory capacitor 400b (including gate isolation and gate electrode, as per [reference]). Figures 3A to 3E (As described in the gate isolation 306 and gate electrode 308).

[0072] In a field-effect transistor structure (e.g., in field-effect transistor structure 400a), there may be (typically inherently) a gate leakage current I.LEAK, FET This leads to charge transfer between the gate electrode and the channel region of the field-effect transistor structure. For example, due to the size of the gate isolation, this can result in leakage current and / or tunneling current through grain boundaries, or other defects in the crystal structure of one or more materials forming the gate isolation. For example, leakage current I increases as the amount of charge stored in the memory capacitor decreases over time. LEAK, CAP This leakage current may be present in the memory capacitor (e.g., in memory capacitor 400b), which can be detrimental to data retention. Various aspects can be addressed by adjusting the memory capacitor stack, such as at least one of the electrodes, to reduce or prevent leakage current in the memory capacitor.

[0073] Depending on the specific aspects, the properties and / or structure of electrodes, electrode layers, and / or functional layers as described herein can be evaluated using techniques known in the art. For example, transmission electron microscopy (TEM) can be used to determine the structure of layers (e.g., electrodes), such as to determine the presence of one or more sublayers (e.g., the presence of one or more electrode layers and / or the presence of one or more functional layers within an electrode). TEM can be used to identify layers, interfaces, crystal structures, microstructures, and other properties. As another example, X-ray crystallography (X-ray diffraction) can be used to determine various properties of layers or materials, such as crystal structure, lattice properties, unit cell size and shape, chemical composition, phase or phase change, the presence of stress in the crystal structure, microstructure, etc. As another example, energy-dispersive X-ray spectroscopy (EDS) can be used to determine the chemical composition of layers or materials, such as the presence and / or abundance of elements in the layers or materials. As yet another example, Rutherford backscattering spectroscopy (RBS) can be used to determine the structure and / or composition of materials. As yet another example, secondary ion mass spectrometry (SIMS) can be used to analyze the molecular composition of a single layer of a solid, such as to analyze the spatial distribution (e.g., gradient) of elements throughout the solid. As another example, neutron diffraction (also known as elastic neutron scattering) can be used to determine the atomic structure of a material.

[0074] Figures 5A to 5DPossible implementations of corresponding electrodes 500a, 500b, 500c, and 500d are schematically shown. These electrodes 500a, 500b, 500c, and 500d may be electrodes of memory capacitors (e.g., these electrodes 500a, 500b, 500c, and 500d may be one of the first electrodes 322 and 402 and / or the second electrodes 326 and 404 of memory capacitors 302b and 400b). In some aspects, electrodes 500a, 500b, 500c, and 500d may include one or more electrode layers 502 and one or more functional layers 504, as described in further detail below. Various electrode layers 502 may be referred to below, such as first electrode layer 502-1, second electrode layer 502-2, third electrode layer 502-3, fourth electrode layer 502-4, etc., which may be collectively referred to as electrode layers 502. Various functional layers 504 may be mentioned in the following text, such as the first functional layer 504-1, the second functional layer 504-2, the third functional layer 504-3, etc., which can be collectively referred to as functional layers 504.

[0075] In some aspects, the electrodes 500a, 500b, 500c, and 500d described herein may be multilayer electrodes comprising multiple electrode layers 502, wherein one of the electrode layers 502 may be in direct physical contact with a memory structure (e.g., memory structures 324, 406). Illustratively, when electrodes 500a, 500b, 500c, and 500d are bottom electrodes, the electrode layer 502 in direct physical contact with the memory structure may be the uppermost electrode layer, or when electrodes 500a, 500b, 500c, and 500d are top electrodes of a memory capacitor, it may be the lowermost electrode layer.

[0076] In some aspects, each electrode layer 502 of electrodes 500a, 500b, 500c, and 500d may have the same lateral dimension. Illustratively, one or more electrode layers 502 of electrodes 500a, 500b, 500c, and 500d may form electrodes 500a, 500b, 500c, and 500d, that is, one or more electrode layers 502 may together provide the functionality associated with electrodes 500a, 500b, 500c, and 500d.

[0077] In some aspects, electrode layer 502 may be coupled to the gate structure of a field-effect transistor structure (e.g., the gate structure of field-effect transistor structures 302a, 400a). In some aspects, electrode layer 502 may be different from the gate electrode of the gate structure, for example, it may not be part of the gate electrode.

[0078] In some aspects, the electrodes 500a, 500b, 500c, and 500d described herein can be configured such that at least one characteristic suitable for influencing the memory structure is gradually varied across the plurality of electrode layers 502 until it reaches a desired value in the electrode layer that is in direct physical contact with the memory structure. The multilayer electrodes can influence the memory structure during their formation (e.g., during deposition or growth) such that the memory structure formed on the multilayer electrodes has one or more desired characteristics (e.g., a desired average grain size, a desired grain size distribution, as examples).

[0079] Various aspects may be based on the understanding that the characteristics (e.g., microstructure characteristics) of the electrodes, possibly due to their formation on the substrate or buffer layer, may not be well-suited for forming memory structures on the electrodes. Various aspects may be based on gradually adjusting the characteristics of the electrodes across their bulk, from those suitable for their formation on the substrate (e.g., on the insulating layer 342 or on the contact structure 344, such as...). Figure 3C The characteristics formed (as shown) are suitable for forming improved memory structures on them (e.g., memory structures that can switch from one state to another more quickly or have improved data retention capabilities, as an example).

[0080] Various aspects can be based on the understanding that although adapted (e.g., multilayer) electrodes as described herein may be more expensive and / or more difficult to manufacture and therefore not used in typical memory cells or typical memory capacitors, the adaptation of electrode characteristics can provide superior performance for memory cells, as described in further detail below.

[0081] In some aspects, electrodes 500a, 500b, 500c, and 500d may have a thickness in the range of about 1 nm to about 50 nm (e.g., about 1 nm to about 30 nm, or about 5 nm to about 20 nm). The thickness of electrodes 500a, 500b, 500c, and 500d can be understood as the total thickness provided by the respective thicknesses of one or more electrode layers 502 and one or more functional layers 504.

[0082] In some aspects, electrode layer 502 may be a conductive layer. Electrode layer 502 may include a conductive material, such as a metallic material or any other conductive material (e.g., a metal alloy, a degenerate semiconductor, a polycrystalline silicon layer, etc.). In some aspects, the material of electrode layer 502 may include at least one of, for example, platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), and cobalt (Co). In some aspects, the material of electrode layer 502 may have a temperature greater than 10 °C at 20 °C. 6The conductivity is S / m. In some aspects, the electrode layer 502 may include a thickness of less than 10 nm, such as less than 5 nm, such as less than 2 nm, such as a thickness in the range of about 0.1 nm to about 1 nm, such as a thickness in the range of about 0.2 nm to about 0.5 nm.

[0083] In some aspects, electrodes 500a, 500b, 500c, and 500d described herein may include a conductivity gradient across the electrodes. Illustratively, electrodes 500a, 500b, 500c, and 500d may include an initial electrode layer with an initial conductivity furthest from the memory structure, and may include a final electrode layer with a final conductivity located at the interface region between electrodes 500a, 500b, 500c, and 500d and the memory structure. In some aspects, the final conductivity may be less than the initial conductivity (e.g., the final conductivity may be an order of magnitude smaller than the initial conductivity, or at least twice as small as the initial conductivity). This allows, for example, the charge stored in the memory structure to be kept confined therein, thereby reducing leakage current in the memory capacitors. In some aspects, the final conductivity may be greater than the initial conductivity (e.g., the final conductivity may be an order of magnitude larger than the initial conductivity, or at least twice as large as the initial conductivity). This can provide, for example, improved state switching of the memory structure. In some respects, the electrical conductivity of a layer can be understood as the electrical conductivity of the material of the layer, such as the electrical conductivity of the main components of the layer or the average electrical conductivity provided by the material comprising the layer.

[0084] In some aspects, the material of electrode layer 502 may have a microstructure, illustratively, one or more microstructure properties. As used herein, the microstructure or microstructure property may include at least one of the following: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type, and / or defect chemical composition. In some aspects, the defect may be an interstitial defect, such as an oxygen interstitial spacer.

[0085] In some aspects, the electrodes 500a, 500b, 500c, and 500d described herein may include a gradient of at least one microstructural property across the electrodes. Illustratively, electrodes 500a, 500b, 500c, and 500d may include an initial electrode layer comprising a material having initial microstructural properties furthest from the memory structure, and may include a final electrode layer comprising a material having final microstructural properties at the interface region between the final electrode layer and the memory structure. The final electrode layer may have microstructures (e.g., microstructures having a reduced average particle size or microstructures having an increased average particle size) that provide a desired microstructure in the memory structure formed thereon.

[0086] In some aspects, the material of electrode layer 502 may have a crystal structure, such as a cubic crystal structure, a monoclinic crystal structure, a tetragonal crystal structure, or a hexagonal crystal structure. The crystal structure of the electrode layer material may have one or more crystal structure properties, which may include: lattice constant, symmetry (e.g., point symmetry), bond length, atomic packing factor, number of atoms per unit cell, etc.

[0087] In some aspects, the electrodes 500a, 500b, 500c, and 500d described herein may include a gradient of crystal structures across the electrodes. Illustratively, electrodes 500a, 500b, 500c, and 500d may include an initial electrode layer comprising a material having an initial crystal structure (possessing initial crystal structure properties) furthest from the memory structure, and may include a final electrode layer comprising a material having a final crystal structure (possessing final crystal structure properties) at the interface region between the final electrode layer and the memory structure. The final electrode layer 502 may have a crystal structure (e.g., a crystal structure with high symmetry) that provides a desired crystal structure in the memory structure formed thereon.

[0088] In some respects, the same material can have different crystal structures (e.g., one or more different crystal properties). For example, the same material with different proportions of participating elements may have different crystal structures, such as crystal structures belonging to the same category (e.g., cubic, tetragonal, etc.) but having one or more different crystal structure properties (e.g., different lattice constants, different bond lengths, etc.). In some respects, different materials can have the same crystal structure, such as crystal structures belonging to the same category (e.g., cubic, tetragonal, etc.) and / or having one or more identical crystal structure properties (e.g., identical lattice constants, identical bond lengths, etc.).

[0089] In some aspects, the final electrode layer 502 of electrodes 500a, 500b, 500c, and 500d may be configured to provide epitaxial growth of a memory structure (e.g., a residual polarization layer) formed thereon. Illustratively, the electrode layer 502 of electrodes 500a, 500b, 500c, and 500d that is in direct contact with the memory structure (e.g., the electrode layer 502 on which a memory structure is formed or should be formed) can be understood as an optimal seed layer to provide the desired characteristics of the memory structure (e.g., desired microstructure, desired crystal structure, as an example).

[0090] Functional layer 504 may be a layer configured to provide a specific function in electrodes 500a, 500b, 500c, 500d. In some aspects, functional layer 504 may be configured to influence the characteristics of another layer formed thereon (e.g., electrode layer 502 or a layer of a memory structure). In some aspects, functional layer 504 may be configured to provide an oxygen diffusion barrier to reduce or prevent oxygen diffusion through electrode 502 (illustratively, through the layer forming electrode 502). In some aspects, the functional layer may define a transition region from a first portion of electrodes 500a, 500b, 500c, 500d having one or more first characteristics to a second portion of electrodes 500a, 500b, 500c, 500d having one or more second characteristics.

[0091] As used herein, in some aspects, the term "functional layer" can describe an interface region (also referred to herein as an interface portion) between two layers (e.g., between an electrode layer and another electrode layer or between an electrode layer and a layer of a memory structure). For example, an interface region may include the uppermost portion of a lower layer and the lowermost portion of an upper layer. An interface region can be understood as a transitional region where the properties of a layer change or begin to change. Illustratively, layers may have certain properties (e.g., certain microstructures, certain conductivities, etc.), and the interface region may have different properties relative to other parts of the layer (e.g., relative to the interior of the layer (illustratively, the bulk)). In some aspects, an interface region can be a perfect interface between two layers, such as where the elements (atoms) of the two layers are not mixed. In other aspects, an interface region may include a mixture of elements of the two layers and may illustratively extend into both layers (e.g., reaching three monolayers in the direction of the first layer and three monolayers in the direction of the second layer, as a numerical example). In some aspects, an interface region can be understood as distinct layers, such as in the case where the interface region extends more than three monolayers into the first layer and more than three monolayers into the second layer. In some aspects, the term "functional layer" as used herein can describe an additional layer inserted between two layers, i.e., a different layer relative to the two layers (e.g., comprising different materials). In some aspects, the functional layer inserted between two layers can be a single layer comprising materials different from the two layers; for example, the functional layer can be a single layer of electrically insulating material inserted between two electrode layers comprising conductive materials.

[0092] In some aspects, the functional layer 504 may have a thickness in the range of about 0.1 nm to about 5 nm, for example, less than 1 nm, or less than 5 nm, or less than 2 nm. Therefore, the functional layer 504 as described herein can be distinguished from electrically insulating layers (e.g., liners) commonly used in the art to fabricate electrodes, memory cells, or memory capacitors, because such electrically insulating layers have a much larger thickness to provide electrical isolation. Therefore, the thin functional layer as described herein will not be implemented in those structures (e.g., as part of metallization). The functional layers described herein are used for quite different purposes, namely, influencing the properties of layers formed on the functional layer and / or providing an oxygen barrier for reducing or preventing oxygen diffusion, as described in further detail below.

[0093] In some respects, the thickness of functional layer 504 allows the overall high voltage conductivity (or high current conductivity) of electrodes 500a, 500b, 500c, and 500d to remain substantially unchanged. Illustratively, the thickness of functional layer 504 allows electrodes 500a, 500b, 500c, and 500d to still be used to allow write or read operations on memory capacitors without increasing the write or read voltage. The thickness of functional layer 504 allows the conductivity of electrodes 500a, 500b, 500c, and 500d to remain substantially unchanged when voltages greater than 0.5 V or greater than 1 V are provided at electrodes 500a, 500b, 500c, and 500d.

[0094] In some aspects, functional layer 504 may include an electrically insulating material, such as a dielectric material, such as an electrically insulating oxide or electrically insulating nitride material (e.g., alumina, aluminum nitride, silicon oxide, silicon nitride, silicon oxynitride, Al2O3, AlN, AlO). x N y Or SiO2, SiN, SiIO x N y (As an example). In some aspects, functional layer 504 may include conductive materials, such as metallic materials, metal alloys, conductive oxide materials, and conductive nitride materials, such as tantalum nitride, indium oxide, copper silicide, tungsten nitride, titanium nitride, ruthenium oxide, rhenium oxide, iridium oxide, etc. In some aspects, the material of functional layer 504 may include at least one of the following: germanium (Ge), platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), cobalt (Co), hafnium (Hf), lanthanum (La), nickel (Ni), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), indium (In), vanadium (V), silicon (S), and / or corresponding oxides and / or corresponding nitrides.

[0095] In some aspects, the material of the functional layer 504 may be selected based on the material of the adjacent electrode layers 502, for example, based on the material of one of the adjacent electrode layers 502. In some aspects, the material of the functional layer 504 may be a metal oxide comprising the metal material of the adjacent electrode layers 502. For example, the material of the electrode layers 502 may include ruthenium, and the material of the adjacent functional layer 504 may include ruthenium oxide.

[0096] In some aspects, functional layer 504 may be configured to reduce or prevent oxygen diffusion in electrodes 500a, 500b, 500c, 500d, for example, oxygen diffusion in adjacent electrode layer 502. Functional layer 504 may be configured as an oxygen diffusion barrier for adjacent electrode layer 502. Illustratively, the oxygen diffusion rate in functional layer 504 (also referred to herein as oxygen diffusivity) may be less than the oxygen diffusion rate in electrode layer 502. In some aspects, the material of electrode layer 502 may strongly attract (and absorb) oxygen, which would reduce the conductivity of electrode layer 502 (e.g., in the case where the material of electrode layer 502 includes Ti). Electrode layer 502 may attract oxygen from, for example, a memory structure (e.g., from an oxygen-containing layer of the memory structure) such that the memory characteristics (e.g., remanent polarization characteristics) of the memory structure may degrade. Functional layer 504 disposed between electrode layer 502 and memory structure may be configured to reduce or prevent oxygen diffusion from memory structure to electrode layer 502. In some respects, the oxygen diffusivity of a layer can be understood as the oxygen diffusivity of the material of the layer, such as the oxygen diffusivity of the main components of the layer or the average oxygen diffusivity provided by the material comprising the layer.

[0097] In some aspects, the functional layer 504 can be configured to absorb oxygen, for example, it can be configured as an oxygen trapping layer. The material of the functional layer 504 (e.g., chromium) can be attractive to oxygen, causing oxygen to be absorbed into the functional layer 504, thereby forming an oxide. After the oxide is formed, further oxidation of the electrode layer 502 disposed below the functional layer 504 and the material of the functional layer 504 can be prevented.

[0098] In some aspects, functional layer 504 may be patterned. Illustratively, in some aspects, functional layer 504 may be a discontinuous layer comprising one or more islands, or a continuous layer comprising one or more vias. In some aspects, this can provide increased conductivity for electrodes 500a, 500b, 500c, 500d, while balancing the barrier properties and / or growth effect properties of patterned functional layer 504.

[0099] In some aspects, such as Figure 5AAs shown, electrode 500a may include electrode layer 502 and functional layer 504 in direct contact with electrode layer 502. Functional layer 504 may be configured to reduce or prevent oxygen diffusion into electrode layer 502. Illustratively, functional layer 504 may be an oxygen barrier layer that reduces or prevents oxygen diffusion into electrode layer 502. In some aspects, functional layer 504 may be in direct contact with memory structures (e.g., with memory structures 324, 406). Functional layer 504 may be in direct contact with layers of memory structures comprising oxygen-containing materials (e.g., with residual polarization layers comprising hafnium oxide and / or zirconium oxide). Functional layer 504 may be configured to prevent oxygen diffusion from memory structures (from oxygen-containing layers) into electrode layer 502. Figure 5A In this context, functional layer 504 is shown as the uppermost layer of electrode 500 (e.g., in the case where electrode 500a is the bottom electrode of a memory capacitor); however, it should be understood that functional layer 504 may additionally or alternatively be the lowermost layer of electrode 500, for example, in the case where electrode 500a is the top layer of a memory capacitor.

[0100] exist Figure 5A In the configuration of electrode 500a shown, a functional layer 504 exists between electrode layer 502 and the memory structure to reduce the capacitance of the memory capacitor. Illustratively, the presence of functional layer 504 can increase the distance between the electrodes of the memory capacitor (e.g., between electrode 500a and another electrode). In some aspects, in addition to providing the aforementioned oxygen diffusion barrier or oxygen absorption function, the material of functional layer 504 can also be conductive. For example, the material of functional layer 504 can be a conductive oxide, such as ruthenium oxide, rhenium oxide, or iridium oxide. The conductive functional layer 504 can reduce or prevent a decrease in the capacitance of the memory capacitor.

[0101] In some aspects, such as Figure 5B As shown, electrode 500b may include a first electrode layer 502-1, a functional layer 504 in direct contact with the first electrode layer 502-1, and a second electrode layer 502-2 in direct contact with the functional layer 504. In the following description of electrode 500b, it is assumed that the second electrode layer 502-2 may (or is intended to) be closer to the memory structure than the first electrode layer 502-1, for example, it is assumed that the second electrode layer 502-2 may be in direct contact with the memory structure. However, it should be understood that the same functionality can be provided when the first electrode layer 502-1 is closer to (or intended to be closer to) the memory structure than the second electrode layer 502-2, for example, when the first electrode layer 502-1 is in direct contact with the memory structure.

[0102] In some aspects, functional layer 504 may be configured to reduce or prevent oxygen diffusion between electrode layers, such as oxygen diffusion from the second electrode layer 502-2 to the first electrode layer 502-1 (or vice versa). In some aspects, the second electrode layer 502-2 may be in direct contact with the memory structure, such as in direct contact with the oxygen-containing layer of the memory structure, and functional layer 504 may be configured to prevent further diffusion of oxygen that may have diffused from the memory structure into the second electrode layer 502-2 into the electrode 500b (e.g., in the first electrode layer 502-1, or in any other electrode layer 502 below). Figure 5B The configuration of electrode 500b shown can provide reduced oxygen diffusion in electrode 500b without reducing the capacitance of the memory capacitor.

[0103] In some aspects, the first electrode layer 502-1 may have a first oxygen diffusivity and the second electrode layer 502-2 may have a second oxygen diffusivity different from the first oxygen diffusivity. The oxygen diffusivity of the different electrode layers (e.g., the first oxygen diffusivity of the first electrode layer 502-1 and the second oxygen diffusivity of the second electrode layer 502-2) may be adapted to provide desired characteristics of a memory structure formed in contact with an electrode (e.g., with electrode 500b), for example, to provide desired oxygen diffusion in the electrode to induce desired polarization characteristics in the memory structure. In some aspects, the second oxygen diffusivity may be less than the first oxygen diffusivity. As a numerical example, the second oxygen diffusivity may be at least 10% or at least 20% smaller than the first oxygen diffusivity. Illustratively, when the second electrode layer 502-2 is closer to the oxygen-rich memory structure or the oxygen-rich layer of the memory structure than the first electrode layer 502-1, the second electrode layer 502-2 may, for example, be combined with the functional layer 504 to provide a barrier preventing oxygen diffusion to the first electrode layer 502-1. In some aspects, the second oxygen diffusivity may be greater than the first oxygen diffusivity. As a numerical example, the second oxygen diffusivity may be at least 10% or at least 20% greater than the first oxygen diffusivity. The second electrode layer 502-2 may allow oxygen diffusion to stop at the interface with the first electrode layer 502-1.

[0104] In some aspects, the functional layer 504 may have an oxygen diffusivity that is less than the first oxygen diffusivity and less than the second oxygen diffusivity. The functional layer 504 may provide an additional oxygen diffusion barrier in the electrode 500b.

[0105] In some aspects, functional layer 504 may have an oxygen diffusivity greater than a first oxygen diffusivity and less than a second oxygen diffusivity (or less than a first oxygen diffusivity and greater than a second oxygen diffusivity). Illustratively, in some aspects, functional layer 504 may have an intermediate oxygen diffusivity between the oxygen diffusivity of adjacent electrode layers 502 (e.g., first electrode layer 502-1 and second electrode layer 502-2). Functional layer 504 may be an interface region (illustratively, a transition region) between first electrode layer 502-1 and second electrode layer 502-2 to provide a desired oxygen diffusion gradient through electrode 500b.

[0106] In some aspects, the first electrode layer 502-1 may have a first conductivity and the second electrode layer 502-2 may have a second conductivity different from the first conductivity. The conductivity of the different electrode layers (e.g., the first conductivity of the first electrode layer 502-1 and the second conductivity of the second electrode layer 502-2) may be adapted to provide desired characteristics of the memory structure and / or memory capacitors, such as a desired range of write voltage and / or read voltage or a desired reduction in leakage current in the memory capacitors, as an example. In some aspects, the second conductivity may be less than the first conductivity. As a numerical example, the second conductivity may be half, one-third, one-fifth, or one-tenth of the first conductivity. A reduced conductivity closer to the memory structure may provide reduced leakage current in the memory capacitors, as described above. In some aspects, the second conductivity may be greater than the first conductivity. As a numerical example, the second conductivity can be twice, three times, five times, or ten times the first conductivity. An increased conductivity closer to that of the memory structure can provide faster control over the state of the memory structure, such as faster switching from a first memory state to a second memory state.

[0107] In some aspects, the functional layer 504 may have a conductivity less than a first conductivity and less than a second conductivity. Illustratively, in some aspects, electrodes 500a, 500b, 500c, and 500d may include electrode layers 502 having reduced conductivity, with a functional layer 504 therebetween to provide, for example, an oxygen diffusion barrier. In some aspects, at a temperature of 20°C, the difference between the conductivity of the functional layer 504 and the conductivity of one of the adjacent electrode layers 502-1 and 502-2 may have a difference of at least 10. 10 The absolute value of S / m.

[0108] In some aspects, functional layer 504 may have a conductivity less than a first conductivity and greater than a second conductivity (or greater than the first conductivity and less than the second conductivity). Illustratively, in some aspects, functional layer 504 may have an intermediate conductivity between the conductivity of adjacent electrode layers (e.g., first electrode layer 502-1 and second electrode layer 502-2). Functional layer 504 may be an interface region (illustratively, a transition region) between first electrode layer 502-1 and second electrode layer 502-2 to provide a desired conductivity gradient.

[0109] In some aspects, the first electrode layer 502-1 may include a first material, and the second electrode layer 502-2 may include a second material different from the first material. In some aspects, the first material of the first electrode layer 502-1 may have a first major component, and the second material of the second electrode layer 502-2 may have a second major component different from the first major component. Illustratively, in some aspects, electrodes 500a, 500b, 500c, and 500d may include a material gradient, from a (first or initial) material suitable for forming electrodes on a substrate to a (second or final) material suitable for forming memory structures on electrodes 500a, 500b, 500c, and 500d.

[0110] In some aspects, the first material of the first electrode layer 502-1 may include a first chemical composition, and the second material of the second electrode layer 502-2 may include a second chemical composition different from the first chemical composition. The first chemical composition may differ from the second chemical composition in at least one aspect of the content and / or doping of the participating elements. In some aspects, the materials of the respective electrode layers may remain unchanged in terms of the main composition or participating elements, but may differ slightly in terms of the relative amounts of the participating elements, for example, by gradually adapting to the characteristics of the electrode layer 502 (e.g., structure, electrical, thermal, etc.) to achieve desired characteristics at the interface with the memory structure.

[0111] In some aspects, the first material of the first electrode layer 502-1 may include a first oxygen weight percentage, and the second material of the second electrode layer 502-2 may include a second oxygen weight percentage different from the first oxygen weight percentage. Changing the oxygen content through the electrode 500b can, for example, adjust the crystal structure of the electrode layer 502 through the electrode to provide a desired crystal structure at the interface with the memory structure. In some aspects, the first oxygen weight percentage may be less than the second oxygen weight percentage (e.g., half, one-third, one-fifth, one-tenth, as examples). In some aspects, the first oxygen weight percentage may be greater than the second oxygen weight percentage (e.g., twice, three times, five times, ten times, as examples). The oxygen content can be adjusted according to the desired characteristics of the memory structure formed or to be formed on the electrodes 500a, 500b, 500c, 500d. In some aspects, the second material of the second electrode layer 502-2, having a larger oxygen weight percentage relative to the first material of the first electrode layer 502-1, can provide an oxygen diffusion barrier function to reduce or prevent oxygen diffusion into the first electrode layer 502-1. In some aspects, a lower oxygen weight percentage in the second material of the second electrode layer 502-2 relative to the first material of the first electrode layer 502-1 can provide a crystal structure of the second material of the second electrode layer 502-2 with a reduced lattice constant, to provide a desired lattice constant in the memory structure formed thereon, as an example. It is understood that the same applies to oxygen volume percentages; for example, the first material of the first electrode layer 502-1 may include a first oxygen volume percentage, and the second material of the second electrode layer 502-2 may include a second oxygen volume percentage different from (e.g., less than or greater than) the first oxygen volume percentage.

[0112] In some aspects, functional layer 504 may comprise a material having an oxygen weight percentage less than a first oxygen weight percentage and less than a second oxygen weight percentage. Illustratively, in some aspects, electrodes 500a, 500b, 500c, and 500d may comprise electrode layers 502 having a reduced (or increased) oxygen weight percentage, with functional layer 504 therebetween, for example, to provide an (additional) oxygen diffusion barrier. The same applies to the oxygen volume percentage of the material of functional layer 504.

[0113] In some aspects, functional layer 504 may comprise a material having an oxygen weight percentage that is less than a first oxygen weight percentage and greater than a second oxygen weight percentage (or greater than the first oxygen weight percentage and less than the second oxygen weight percentage). Illustratively, in some aspects, the material of functional layer 504 may have an intermediate oxygen weight percentage between the oxygen weight percentages of the materials of adjacent electrode layers 502 (e.g., first electrode layer 502-1 and second electrode layer 502-2). Functional layer 504 may be an interface region between first electrode layer 502-1 and second electrode layer 502-2 to provide a desired oxygen weight percentage gradient. This also applies to the oxygen volume percentage of the material of functional layer 504.

[0114] In some aspects, the first material of the first electrode layer 502-1 may include a first crystal structure, and the second material of the second electrode layer 502-2 may include a second crystal structure different from the first crystal structure. Illustratively, the first material of the first electrode layer 502-1 may include one or more first crystal structure properties (e.g., a first lattice constant, a first point symmetry, a first bond length, a first atomic packing factor, a first number of atoms per unit unit), and the second material of the second electrode layer 502-2 may include one or more second crystal structure properties (e.g., a second lattice constant, a second point symmetry, a second bond length, a second atomic packing factor, a second number of atoms per unit unit), wherein at least one first crystal structure property may differ from a corresponding second crystal structure property. The crystal structure of the electrode layer 502 may be gradually adjusted to provide a desired crystal structure at the interface with the memory structure (e.g., to produce desired crystal structure properties in the memory structure). By way of example only, the first material of the first electrode layer 502-1 may have a larger bond length and / or a larger lattice constant relative to the second material of the second electrode layer 502-2.

[0115] In some aspects, the material of functional layer 504 may have intermediate crystal structure characteristics relative to the crystal structure characteristics of the materials of adjacent electrode layers (e.g., relative to the first crystal structure characteristics and the second crystal structure characteristics). Functional layer 504 may be an interface region between the first electrode layer 502-1 and the second electrode layer 502-2 to provide a desired gradient of crystal structure characteristics. By way of example only, the material of functional layer 504 may have bond lengths greater than the second bond length and less than the first bond length and / or a lattice constant greater than the second lattice constant and less than the first lattice constant.

[0116] In some aspects, the material of the memory structure (e.g., the material of the layers of the memory structure) may include a crystal structure substantially equal to the crystal structure of the electrode layer 502 in direct contact with it. As an example, the material of the memory structure may include a crystal structure substantially equal to a second crystal structure; for example, the material of the memory structure may have crystal structure properties substantially equal to those of the second crystal structure.

[0117] In some aspects, the first material of the first electrode layer 502-1 may include a first microstructure, and the second material of the second electrode layer 502-2 may include a second microstructure different from the first microstructure. Illustratively, the first material of the first electrode layer 502-1 may have one or more first microstructure characteristics (e.g., first grain size, first average grain size, first grain size distribution, first number of grain boundaries, first grain boundary density, first grain boundary shape, first grain boundary chemical composition, a first region between two adjacent grains, first defect content, first defect type, and / or first defect chemical composition), and the second material of the second electrode layer 502-2 may include one or more second microstructure characteristics (e.g., second grain size, second average grain size, second grain size distribution, second number of grain boundaries, second grain boundary density, second grain boundary shape, second grain boundary chemical composition, a second region between two adjacent grains, second defect content, second type of defect, and / or second defect chemical composition), wherein at least one first microstructure characteristic may differ from a corresponding second microstructure characteristic. The microstructure of the electrode layer 502 may be progressively tuned to provide a desired microstructure at the interface with the memory structure.

[0118] In some aspects, the first material of the first electrode layer 502-1 may include a plurality of grains having a first average grain size and / or a first grain size distribution, and the second material of the second electrode layer 502-2 may include a plurality of grains having a second average grain size and / or a second grain size distribution. The first average grain size may be different from the second average grain size and / or the first grain size distribution may be different from the second grain size distribution. Changing the average grain size and / or grain size distribution through the electrode 500b can provide, for example, an adjustment to the crystal structure of the electrode layer 502 through the electrode to provide a desired crystal structure at the interface with the memory structure.

[0119] In some aspects, the first average grain size may be larger than the second average grain size, for example, at least twice or at least three times larger. Providing an electrode layer 502 with a relatively small grain size at the interface with the memory structure can provide an influence on the material of the memory structure (during its formation) such that it comprises relatively small grains (a plurality of grains with a relatively small average grain size), also see... Figure 6B In some aspects, the first average grain size may be smaller than the second average grain size, for example, half or one-third of the second average grain size. Providing an electrode layer 502 with a relatively large grain size at the interface with the memory structure can influence the material of the memory structure (during its formation) such that it comprises relatively large grains (multiple grains with a relatively large average grain size). The average grain size of the grains of the memory structure material can be influenced by the desired characteristics of the memory structure (e.g., electrical and / or polarization characteristics).

[0120] In some aspects, the first grain size distribution may be wider than the second grain size distribution, for example, at least twice or at least three times wider. Providing an electrode layer 502 with a relatively narrow grain size distribution at the interface with the memory structure can influence the material of the memory structure (during its formation) such that it comprises more uniform grains, for example, grains with more uniform sizes relative to each other. In some aspects, the first grain size distribution may be narrower than the second grain size distribution. The grain size distribution of the material of the memory structure may be influenced by the desired characteristics of the memory structure, such as electrical and / or polarization characteristics.

[0121] In some aspects, the material of functional layer 504 may have intermediate microstructure characteristics relative to the microstructure characteristics of the materials of adjacent electrode layers (e.g., relative to the first microstructure characteristic and the second microstructure characteristic). Functional layer 504 may be an interface region between the first electrode layer 502-1 and the second electrode layer 502-2 to provide a desired microstructure characteristic gradient. As an example, the material of functional layer 504 may have an average particle size greater than the second average particle size and less than the first average particle size and / or a particle size distribution wider than the second particle size distribution and narrower than the first particle size distribution.

[0122] In some aspects, the material of the memory structure (e.g., the material of the layers of the memory structure) may include microstructures substantially equal to the microstructures of the electrode layers in direct contact with it. As an example, the material of the memory structure may include microstructures substantially equal to a second microstructure, for example, the material of the memory structure may include microstructure properties substantially equal to the characteristics of the second microstructure. The material of the memory structure may include a plurality of grains having an average grain size substantially equal to a second average grain size and / or a grain size distribution substantially equal to a second grain size distribution. The material of the memory structure may include a plurality of grains with an average grain size smaller than a first average grain size and / or a grain size distribution narrower than a first grain size distribution. Providing a controlled average grain size and / or a controlled grain size distribution of the material of the memory structure allows for the adjustment of the characteristics of the memory structure, such as adjusting its polarization characteristics, for example, to provide stronger ferroelectric behavior.

[0123] In some aspects, the first electrode layer 502-1 may include a first thickness, and the second electrode layer 502-2 may include a second thickness different from the first thickness. Changing the thickness of the electrode layer 502 through electrodes 500a, 500b, 500c, 500d can provide, for example, adjustments to the microstructure and / or crystal structure characteristics of the electrode layer 502 through electrodes 500a, 500b, 500c, 500d to provide a desired microstructure and / or crystal structure at the interface with the memory structure. In some aspects, the first thickness may be less than the second thickness (e.g., one-half, one-third, one-fifth, one-tenth, as examples). In some aspects, the first thickness may be greater than the second thickness (e.g., twice, three times, five times, ten times, as examples). The thickness adjustment can be based on the desired characteristics of the memory structure formed or to be formed on electrodes 500a, 500b, 500c, 500d. In some respects, a second electrode layer 502-2 having a greater thickness than the first electrode layer 502-1 can provide an oxygen diffusion barrier function to reduce or prevent oxygen diffusion into the first electrode layer 502-1.

[0124] It is understood that the structure of electrodes 500a, 500b, 500c, and 500d is not limited to two electrode layers 502, nor is it limited to one functional layer 504. The number of electrode layers 502 and the number of functional layers 504 can be adjusted (e.g., selected) according to the desired characteristics to be provided for forming the memory structure, such as the desired gradient of one or more characteristics to be provided through electrodes 500a, 500b, 500c, and 500d.

[0125] For example, such as Figure 5C As shown, electrode 500c may include multiple functional layers 504, such as a first functional layer 504-1 disposed between a first electrode layer 502-1 and a second electrode layer 502-2 (the first functional layer 504-1 is in direct contact with the first electrode layer 502-1 and the second electrode layer 502-2) and a second functional layer 504-2 in direct contact with the second electrode layer 502-2. The first functional layer 504-1 and the second functional layer 504-2 may be as described above regarding... Figure 5A and Figure 5B The functional layer 504 is configured as described, for example to provide an oxygen diffusion barrier function and / or to provide a gradual change in one or more properties through the electrode 500c.

[0126] For example, such as Figure 5D As shown, electrode 500d may include multiple electrode layers 502 and multiple functional layers 504. Figure 5DIn the exemplary configuration shown, electrode 500d may include a first electrode layer 502-1, a second electrode layer 502-2, a third electrode layer 502-3, and a fourth electrode layer 502-4; a first functional layer 504-1 disposed between (and in direct contact with) the first electrode layer 502-1 and the second electrode layer 502-2; a second functional layer 504-2 disposed between (and in direct contact with) the second electrode layer 502-2 and the third electrode layer 502-3; and a third functional layer 504-3 disposed between (and in direct contact with) the third electrode layer 502-3 and the fourth electrode layer 502-4. Figure 5D In the exemplary configuration, it may be assumed that the fourth electrode layer 502-4 can (or is intended) be closer to the memory structure than the other electrode layers 502, for example, it may be assumed that the fourth electrode layer 502-4 can be in direct contact with the memory structure.

[0127] In some aspects, each electrode layer 502 may have varying properties relative to previous (and subsequent) electrode layers 502. As an example, the third material of the third electrode layer 502-3 may have a third microstructure different from the first and second microstructures. The fourth material of the fourth electrode layer 502-4 may have a fourth microstructure different from the first, second, and third microstructures, etc. As described above, one or more gradients of properties can be provided across electrodes 500a, 500b, 500c, and 500d.

[0128] For example, the third material may include a plurality of grains having a third average grain size and a third grain size distribution. The fourth material may include a plurality of grains having a fourth average grain size and a fourth grain size distribution. For example, the relationship between average grain sizes may be first average grain size > second average grain size > third average grain size > fourth average grain size. In some aspects, the relationship between average grain sizes may be first average grain size < second average grain size < third average grain size < fourth average grain size. For example, the relationship between grain size distributions may be that the first grain size distribution is wider than the second grain size distribution, the second grain size distribution is wider than the third grain size distribution, and the third grain size distribution is wider than the fourth grain size distribution. As another example, the relationship between grain size distributions may be that the first grain size distribution is narrower than the second grain size distribution, the second grain size distribution is narrower than the third grain size distribution, and the third grain size distribution is narrower than the fourth grain size distribution.

[0129] As another example, the third electrode layer 502-3 may include a third conductivity and the fourth electrode layer 502-4 may include a fourth conductivity. The relationship between the conductivityes may, for example, be first conductivity > second conductivity > third conductivity > fourth conductivity. In some aspects, as another example, the relationship between the conductivityes may be first conductivity < second conductivity < third conductivity < fourth conductivity.

[0130] As another example, the third material may include a crystal structure having a third bond length and a third lattice constant, and the fourth material may include a crystal structure having a fourth bond length and a fourth lattice constant. For example, the relationship between bond lengths may be first bond length > second bond length > third bond length > fourth bond length, and / or the relationship between lattice constants may be first lattice constant > second lattice constant > third lattice constant > fourth lattice constant. In some aspects, for example, the relationship between bond lengths may be first bond length < second bond length < third bond length < fourth bond length, and / or the relationship between lattice constants may be first lattice constant < second lattice constant < third lattice constant < fourth lattice constant.

[0131] As another example, the third material may have a third thickness, and the fourth material may have a fourth thickness. For example, the relationship between the thicknesses of the electrode layer 502 may be first thickness > second thickness > third thickness > fourth thickness. In some aspects, as another example, the relationship between the thicknesses of the electrode layer 502 may be first thickness < second thickness < third thickness < fourth thickness.

[0132] As another example, the third material may have a third oxygen weight percentage, and the fourth material may have a fourth oxygen weight percentage. For example, the relationship between the oxygen weight percentages of electrode layer 502 may be first oxygen weight percentage > second oxygen weight percentage > third oxygen weight percentage > fourth oxygen weight percentage. In some aspects, as another example, the relationship between the oxygen weight percentages of electrode layer 502 may be first oxygen weight percentage < second oxygen weight percentage < third oxygen weight percentage < fourth oxygen weight percentage.

[0133] In some aspects, each functional layer 504 (e.g., first functional layer 504-1, second functional layer 504-2, third functional layer 504-3) can be adjusted according to adjacent electrode layers. Illustratively, the characteristics of functional layers 504-1, 504-2, 504-3 (e.g., the material properties of functional layers 504-1, 504-2, 504-3) can be intermediate characteristics relative to adjacent electrode layers; that is, functional layers 504-1, 504-2, 504-3 can provide transition regions for providing a desired gradient, as described above.

[0134] In some aspects, each functional layer 504 (e.g., first functional layer 504-1, second functional layer 504-2, third functional layer 504-3) may be configured to provide an oxygen diffusion barrier to adjacent electrode layers, as described above.

[0135] Figure 6A and Figure 6BRespective portions of memory capacitors 600a and 600b are shown respectively. Memory capacitor 600a may include an electrode 602a that is not adapted as described herein, while memory capacitor 600b may include an electrode 602b that is adapted as described herein (illustratively, electrode 602b may be configured as described regarding...). Figures 5A to 5D The described electrode 500).

[0136] The electrode 602a of the memory capacitor 600a may include a continuous crystalline electrode layer, i.e., a continuous layer extending to the memory structure 604a of the memory capacitor 600a (e.g., to the residual polarization layer, such as a ferroelectric layer). The material of the electrode 602a may include a plurality of grains 606a having a specific grain size (average grain size), which, as described above, can be relatively large compared to the grain size obtainable by adapting the electrode 602b.

[0137] The electrode 602b of the memory capacitor 600b may include multiple (e.g., two or more, e.g., four or more) electrode layers 610-1, 610-2, 610-3, 610-4 and multiple (e.g., two or more, e.g., four or more) functional layers 612-1, 612-2, 612-3 to provide a gradient of various characteristics across the electrode 602b, such that the electrode layer 610-4, which is in direct contact with the memory structure 604b of the memory capacitor 600b (e.g., in direct contact with a residual polarization layer such as a ferroelectric layer), may have desired characteristics. Figure 6B In the exemplary configuration shown, electrode layers 610-1, 610-2, 610-3, 610-4 and functional layers 612-1, 612-2, 612-3 can be configured to provide a gradient in the average grain size across electrode 602b, such that the material of electrode layer 610-4 may include a plurality of grains 606b having a desired grain size, for example with... Figure 6A The electrode 602a shown has a relatively small grain size. This allows the memory structure 604b to have desired characteristics, such as the material of the memory structure having multiple grains 608b with a desired (e.g., relatively small) grain size.

[0138] Figure 7 A schematic flowchart illustrating a method 700 for forming a memory capacitor according to various aspects is shown. In some aspects, the method 700 for forming a memory capacitor may include one or more processes configured to form electrodes 500a, 500b, 500c, 500d as described herein.

[0139] Depending on various aspects, method 700 for forming a memory capacitor may include: forming a first electrode in 710, forming a memory structure in direct contact with the first electrode in 720, and forming a second electrode in direct contact with the memory structure in 730. The first electrode, the memory structure, and the second electrode may form a memory capacitor. Forming at least one of the first electrode and forming the second electrode may include forming a first electrode layer using first process parameters and forming a second electrode layer using second process parameters different from the first process parameters. Illustratively, forming at least one of the first electrode and forming the second electrode may include changing process parameters during electrode formation to provide varying characteristics across the electrode, for example, to provide a gradient of one or more characteristics across the electrode. In some aspects, the memory structure formed in process 720 of method 700 may include memory structures 324, 406, and 504 as described herein. In some aspects, the first electrode formed in process 710 of method 700 may include electrodes 322, 402, 500a, 500b, 500c, and 500d as described herein. In some aspects, the second electrode formed in process 730 of method 700 may include electrodes 326, 404, 500a, 500b, 500c, and 500d as described herein. In some aspects, the memory capacitor formed in processes 710, 720, and 730 of method 700 may include memory capacitors 200b, 302b, and 400b as described herein.

[0140] It is understood that method 700 is not limited to forming a first electrode layer and a second electrode layer, and in some aspects may include forming one or more additional electrode layers (e.g., a third electrode layer, a fourth electrode layer, etc.), each associated with corresponding process parameters.

[0141] In some aspects, the formation of the memory structure 720 of method 700 may include forming a memory structure in direct physical contact with a second electrode layer, and the second electrode layer may be configured to influence one or more characteristics of the memory structure during the formation of the memory structure. Illustratively, the second electrode layer may be configured to provide desired characteristics to the memory structure. In some aspects, the formation of the memory structure 720 of method 700 may include epitaxially growing the memory structure on the second electrode layer.

[0142] In some aspects, method 700 may include one or more layering and patterning processes for processing memory capacitors (e.g., for forming memory structures and / or electrodes). In some aspects, a mask may be used. The mask may include a material for transferring a photolithographic mask pattern into one or more material layers. The mask may include, for example, positive or negative photoresist (also known as a soft mask) or a hard mask. The photoresist itself may be patterned using standard photolithography processes. Patterning of the hard mask material may include a combination of photoresist patterning and subsequent etching of the hard mask material (e.g., wet or dry chemical etching). However, any other suitable process may be used to transfer the desired pattern into one or more material layers.

[0143] In various aspects, forming electrodes 710, 730 may include depositing or growing multiple electrode layers. The process parameters associated with the electrode layers may be deposition parameters or growth parameters. The deposition or growth of the electrode layers may be performed using techniques known in the art, such as sputtering, electron beam evaporation, chemical vapor deposition, thermal vapor deposition, nucleation, etc. In some aspects, the deposition or growth of the electrode layers may be performed in a vacuum chamber.

[0144] In some aspects, the process parameters associated with different electrode layers may differ in at least one of the following aspects (e.g., a first process parameter may differ from a second process parameter in at least one of the following aspects): processing temperature, processing pressure, precursor material, process gas (e.g., process gas flow), and / or partial pressure of the process gas. Illustratively, method 700 may include one or more interruptions or interruptions during the formation of an electrode to modify one or more process parameters associated with that electrode to provide multiple electrode layers within the electrode.

[0145] In some aspects, the processing temperature associated with the electrode layer may vary by at least 5%, or at least 20%, or at least 50%, or at least 100% relative to the processing temperature associated with the (immediately following) preceding electrode layer. As an example, a second temperature at which a second electrode layer is formed (e.g., deposited) beneath it may be 5% greater than a first temperature at which a first electrode layer is formed beneath it, and in some aspects, 10%, 50%, or 100% greater. As another example, a second temperature at which a second electrode layer is formed (e.g., deposited) beneath it may be 5% less than a first temperature at which a first electrode layer is formed beneath it, and in some aspects, 10% or 50% less. The temperature may be increased or decreased depending on the characteristics to be provided in the formed electrode layer.

[0146] In some aspects, the processing pressure associated with the electrode layer may vary by at least 5%, or at least 20%, or at least 50%, or at least 100% relative to the processing pressure associated with the (immediately following) preceding electrode layer. As an example, the second pressure under which the second electrode layer is formed (e.g., deposited) may be 5% greater than the first pressure under which the first electrode layer is formed, and in some aspects, 10%, 50%, or 100% greater. As another example, the second pressure under which the second electrode layer is formed (e.g., deposited) may be 5% less than the first pressure under which the first electrode layer is formed, and in some aspects, 10% or 50% less. The pressure may be increased or decreased depending on the characteristics to be provided in the formed electrode layer.

[0147] In some aspects, the precursor material used to form the electrode layer may vary relative to the precursor material associated with the (immediately following) electrode layer. Forming the first electrode layer may include using a first precursor material, and forming the second electrode layer may include using a second precursor material that is different from the first precursor material. The first precursor material may differ from the second precursor material in at least one of the following aspects: electrical conductivity, chemical composition, and / or the content of participating elements.

[0148] In some aspects, the process gas used during the formation of the electrode layer may vary relative to the process gas used during the formation of the preceding electrode layer. Forming the first electrode layer may include using a first process gas, and forming the second electrode layer may include using a second process gas different from the first process gas. The first process gas may differ from the second process gas in at least one of the following aspects: chemical composition and / or the content of participating elements. In some aspects, the flow rate (e.g., volume per minute or volume per second) of the process gas used during the formation of the electrode layer may vary by at least 5%, or at least 20%, or at least 50%, or at least 100% relative to the flow rate used during the formation of the preceding electrode layer. For example, the second gas flow rate under which the second electrode layer is formed (e.g., deposited) may be 5% greater than the first gas flow rate under which the first electrode layer is formed, and in some aspects, 10%, 50%, or 100% greater. As another example, the second gas flow rate under which the second electrode layer is formed (e.g., deposited) may be 5% less than the first gas flow rate under which the first electrode layer is formed, and in some aspects, 10% or 50% less. The gas flow rate can be increased or decreased depending on the characteristics to be provided in the formed electrode layer.

[0149] In some aspects, the amount of oxygen used during the formation of the electrode layer (e.g., the amount of oxygen introduced into the vacuum chamber during the formation of the electrode layer) may vary by at least 5%, or at least 20%, or at least 50%, or at least 100% relative to the amount of oxygen associated with the (immediately following) preceding electrode layer. For example, the second amount of oxygen used during the formation of the second electrode layer may be 5% greater than the first amount of oxygen used during the formation of the first electrode layer, and in some aspects, 10%, 50%, or 100% greater. As another example, the second amount of oxygen used during the formation of the second electrode layer may be 5% less than the first amount of oxygen used during the formation of the first electrode layer, and in some aspects, 10% or 50% less. The amount of oxygen may be increased or decreased depending on the characteristics to be provided in the formed electrode layer.

[0150] In some aspects, the partial pressure of the process gas (e.g., oxygen) used during the formation of the electrode layer (e.g., the partial pressure of oxygen introduced into the vacuum chamber during the formation of the electrode layer) may vary by at least 5%, or at least 20%, or at least 50%, or at least 100% relative to the partial pressure of the process gas associated with the (immediately following) preceding electrode layer. For example, the second oxygen partial pressure used during the formation of the second electrode layer may be 5% greater than the first oxygen partial pressure used during the formation of the first electrode layer, and in some aspects, 10%, 50%, or 100% greater. As another example, the second oxygen partial pressure used during the formation of the second electrode layer may be 5% less than the first oxygen partial pressure used during the formation of the first electrode layer, and in some aspects, 10% or 50% less. The partial pressure may be increased or decreased depending on the characteristics to be provided in the formed electrode layer.

[0151] In some aspects, method 700 may include forming a functional layer between two electrode layers. For example, method 700 may include forming the functional layer after forming a first electrode layer (e.g., the functional layer is in direct contact with the first electrode) and before forming a second electrode layer (e.g., in direct contact with the functional layer). In some aspects, the functional layer formed in method 700 may include functional layer 504 as described herein. The functional layer may be configured to influence one or more properties of the electrode layers formed thereon, for example, the functional layer may be configured to influence one or more properties of the second electrode layer during the formation of the second electrode layer.

[0152] In some aspects, forming a functional layer may include forming (e.g., depositing or growing) an additional layer over the electrode layer. In some aspects, forming a functional layer may include forming a monolayer of an electrically insulating material (e.g., an electrically insulating oxide, such as alumina) over the electrode layer.

[0153] In some aspects, forming a functional layer may include creating a transition (illustratively, a conversion) at the surface of the electrode layer prior to the formation of a subsequent electrode layer. Illustratively, forming a functional layer may include initiating the formation of an interface region on which a subsequent electrode layer may be formed. For example, the interface region may be provided by temperature processing of the electrode layer, or by waiting a predetermined waiting time prior to the formation of the subsequent electrode layer to allow atoms at the surface of the electrode layer to exhibit a desired configuration.

[0154] In some aspects, method 700 may include waiting for a predetermined waiting time between the formation of successive electrode layers, for example, after the formation of the first electrode layer and before the formation of the second electrode layer. The predetermined waiting time may be sufficient to allow the formation of desired interface properties at the surface of the first electrode layer. As numerical examples, the waiting time may be greater than 1 minute, greater than 10 minutes, or greater than 1 hour.

[0155] Figure 8 A schematic flowchart illustrating a method 800 for forming a memory capacitor according to various aspects is shown. In some aspects, the method 800 for forming a memory capacitor may include one or more processes configured to form electrodes 500a, 500b, 500c, 500d as described herein.

[0156] According to various aspects, method 800 for forming a memory capacitor may include: forming a first electrode in 810; forming a memory structure in 820 that is in direct contact with the first electrode, the memory structure including at least one layer having an oxygen-containing material; and forming a second electrode in 830 that is in direct contact with the memory structure. The first electrode, the memory structure, and the second electrode may form a memory capacitor. Forming at least one of the first electrode and forming the second electrode may include forming an electrode layer and a functional layer in direct contact with the oxygen-containing material, wherein the functional layer is configured to reduce or prevent oxygen diffusion from the at least one layer including the oxygen-containing material into the electrode layer. In some aspects, the memory structure formed in process 820 of method 800 may include memory structures 324, 406, and 504 as described herein. In some aspects, the first electrode formed in process 810 of method 800 may include electrodes 322, 402, 500a, 500b, 500c, and 500d as described herein. In some aspects, the second electrode formed in process 830 of method 800 may include electrodes 326, 404, 500a, 500b, 500c, and 500d as described herein. In some aspects, the memory capacitor formed in processes 810, 820, and 830 of method 800 may include memory capacitors 200b, 302b, and 400b as described herein.

[0157] Depending on the specifics, memory cells as described herein can be integrated into electronic devices (e.g., microcontrollers, central processing units, system-on-a-chip (SoC), memory devices), for example, within the same electronic device having other elements (such as elements for controlling the logic operations and / or input / output operations of the electronic device). Illustratively, one or more memory transistors can be integrated (and formed) on or within the same carrier with one or more logic transistors and / or one or more input / output transistors.

[0158] The term "above" used in this document to describe the formation of a feature, such as forming a layer "above" a side or surface, can be used to indicate that a feature (e.g., a layer) can be formed "directly" on the referred side or surface, for example, in direct contact with it. The term "above" used in this document to describe the formation of a feature, such as forming a layer "above" a side or surface, can also be used to indicate that a feature (e.g., a layer) can be formed "indirectly" on the referred side or surface, wherein one or more additional layers are arranged between the referred side or surface and the formed layer.

[0159] The term "lateral" is used to describe the lateral dimension (in other words, lateral extent) of a structure, part, structural element, layer, etc., disposed above and / or within or "laterally" adjacent to a carrier (e.g., a layer, substrate, wafer, etc.). In this document, the term "lateral" may be used to indicate extent or positional relationship along the carrier surface. This means that, in some aspects, the surface of the carrier (e.g., the surface of a layer, the surface of a substrate, the surface of a wafer, etc.) may be used as a reference, often referred to as the main processing surface. Furthermore, the term "width," used in relation to the "width" of a structure, part, structural element, layer, etc., may be used herein to describe the lateral dimension (or, in other words, lateral extent) of the structure. Additionally, the term "height," used in relation to the height of a structure, part, structural element, layer, etc., may be used herein to describe the dimension (in other words, extent) of the structure in a direction perpendicular to the carrier surface (e.g., perpendicular to the main processing surface of the carrier).

[0160] The term "connection" as used herein refers to nodes, terminals, integrated circuit elements, etc., to indicate an electrical connection. An electrical connection can include direct or indirect connections, wherein an indirect connection may consist only of additional structures in the current path that do not affect the basic function of the circuit or device. The term "conductive connection," used herein to describe an electrical connection between one or more terminals, nodes, areas, contacts, etc., can be understood as a conductive connection having, for example, ohmic behavior, provided by a metal or degenerate semiconductor in which a pn junction does not exist in the current path. The term "conductive connection" may also be referred to as "energized connection."

[0161] The term "region," as used herein with respect to "source region," "drain region," "channel region," etc., may be used to refer to a continuous region of a semiconductor portion (e.g., a semiconductor wafer or a portion thereof, a semiconductor layer, a fin, a semiconductor nanosheet, a semiconductor nanowire, etc.). In some aspects, the continuous region of a semiconductor portion may be provided by a semiconductor material having only one dominant doping type.

[0162] The term "thickness" as used herein may be used to refer to the dimension (in other words, the extent) of a layer perpendicular to the surface of a support (material or material structure) on which the layer is formed (e.g., deposited or grown). If the surface of the support is parallel to the surface of the carrier (e.g., parallel to the main processing surface), the "thickness" of the layer formed on the surface of the support may be the same as the height of the layer.

[0163] Various aspects of the invention will be shown below.

[0164] Example 1a is a memory cell comprising: a first electrode; a second electrode; and a memory structure disposed between the first electrode and the second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor, wherein at least one of the first electrode and the second electrode comprises: a first electrode layer comprising a first material having a first microstructure; a functional layer in direct contact with the first electrode layer; and a second electrode layer in direct contact with the functional layer, the second electrode layer comprising a second material having a second microstructure different from the first microstructure.

[0165] In Example 2a, the subject matter of Example 1a may optionally also include: the first microstructure differs from the second microstructure in at least one of the following aspects: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type and / or defect chemical composition.

[0166] In Example 3a, the subject matter of Example 1a or 2a may optionally further include: a first material of the first electrode layer comprising a plurality of grains having a first average grain size and / or a first grain size distribution, and a second material of the second electrode layer comprising a plurality of grains having a second average grain size and / or a second grain size distribution, wherein the first average grain size is different from the second average grain size, and / or the first grain size distribution is different from the second grain size distribution.

[0167] In Example 4a, the subject matter of Example 3a may optionally also include: a second average particle size that is smaller than a first average particle size, or a second average particle size that is larger than a first average particle size.

[0168] In Example 5a, the subject matter of Example 3a or 4a may optionally include: a first particle size distribution that is wider than a second particle size distribution, or a first particle size distribution that is narrower than a second particle size distribution.

[0169] In Example 6a, the subject matter of any one of Examples 1a to 5a may optionally also include: the material of the memory structure comprises a plurality of grains, the average grain size of which is substantially equal to the average grain size of a plurality of grains of the second material of the second electrode layer, and / or the average grain size of a plurality of grains of the material of the memory structure is different from (e.g., less than or greater than) the average grain size of a plurality of grains of the first material of the first electrode layer.

[0170] In Example 7a, the subject matter of any one of Examples 1a to 6a may optionally further include: a first material of the first electrode layer having a first oxygen weight percentage, and a second material of the second electrode layer having a second oxygen weight percentage different from the first oxygen weight percentage.

[0171] In Example 8a, the subject of Example 7a may optionally also include: a first oxygen weight percentage is less than a second oxygen weight percentage, or a second oxygen weight percentage is greater than a first oxygen weight percentage.

[0172] It should be noted that, at least when the difference is greater than 1 weight percentage, such as greater than 2 weight percentage, such as greater than 5 weight percentage, the second oxygen weight percentage can be considered different from the first oxygen weight percentage.

[0173] In Example 9a, the subject matter of any one of Examples 1a to 8a may optionally further include: a first material of the first electrode layer comprising a first major component, and a second material of the second electrode layer comprising a second major component different from the first major component.

[0174] In Example 10a, the subject matter of Example 9a may optionally include: a first material having a first chemical composition and a second material having a second chemical composition, wherein the first chemical composition differs from the second chemical composition in at least one aspect of the content and / or doping of the participating elements.

[0175] In Example 11a, the subject matter of any one of Examples 1a to 10a may optionally include: a first material of the first electrode layer having a first crystal structure (e.g., one or more first crystal structure properties), and a second material of the second electrode layer having a second crystal structure (e.g., one or more second crystal structure properties) different from the first crystal structure.

[0176] In Example 12a, the subject matter of any one of Examples 1a to 11a may optionally also include: the first material of the first electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0177] In Example 13a, the subject matter of any one of Examples 1a to 12a may optionally also include: the second material of the second electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0178] In Example 14a, the subject matter of any one of Examples 1a to 13a may optionally include: a first electrode layer having a first thickness, and a second electrode layer having a second thickness different from the first thickness.

[0179] In Example 15a, the subject of Example 14a may optionally include: a first thickness less than a second thickness, or a first thickness greater than a second thickness.

[0180] In Example 16a, the subject matter of any of Examples 1a to 15a may optionally also include: the second electrode layer being configured to be closer to the memory structure relative to the first electrode layer.

[0181] In Example 17a, the subject matter of Example 16a may optionally also include: the memory structure and the second electrode layer being in direct physical contact with each other.

[0182] In Example 18a, the subject matter of any one of Examples 1a to 17a may optionally further include: the functional layer is the interface region between the first electrode layer and the second electrode layer, and includes the uppermost part of the first electrode layer and the lowermost part of the second electrode layer.

[0183] In Example 19a, the subject matter of any one of Examples 1a to 18a may optionally also include: the thickness of the first functional layer is in the range of about 0.1 nm to about 5 nm, for example less than 0.5 nm or less than 0.2 nm.

[0184] In Example 20a, the subject matter of any one of Examples 1a to 19a may optionally include: a first electrode layer having a first conductivity, and a second electrode layer having a second conductivity different from the first conductivity.

[0185] In Example 21a, the subject matter of Example 20a may optionally also include: the functional layer having a conductivity less than a first conductivity and less than a second conductivity.

[0186] In Example 22a, the subject matter of Example 20a or 21a may optionally also include: a second conductivity less than a first conductivity, or a second conductivity greater than a first conductivity.

[0187] In Example 23a, the subject matter of Example 22a may optionally also include: the second conductivity is less than half of the first conductivity, or the second conductivity is at least twice as large as the first conductivity.

[0188] In Example 24a, the subject matter of any one of Examples 1a to 23a may optionally include: the functional layer is an oxygen absorption layer or an oxygen diffusion barrier layer.

[0189] In Example 25a, the subject matter of any one of Examples 1a to 24a may optionally further include: a first electrode layer comprising a first oxygen diffusivity, and a second electrode layer comprising a second oxygen diffusivity different from the first oxygen diffusivity.

[0190] In Example 26a, the subject matter of Example 25a may optionally also include: the functional layer having an oxygen diffusivity that is less than the first oxygen diffusivity and less than the second oxygen diffusivity.

[0191] In Example 27a, the subject matter of Embodiments 25a or 26a may optionally include: a second oxygen diffusivity that is less than a first oxygen diffusivity, or a second oxygen diffusivity that is greater than a first oxygen diffusivity.

[0192] In Example 28a, the subject matter of Example 27a may optionally also include: the second oxygen diffusivity is less than half of the first oxygen diffusivity, or the second oxygen diffusivity is at least twice as large as the first oxygen diffusivity.

[0193] In Example 29a, the subject matter of any one of Examples 1a to 28a may optionally also include: the material of the functional layer includes at least one of oxides, nitrides or oxynitrides.

[0194] In some examples, the material of the functional layer may include at least one of the following: germanium (Ge), platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), cobalt (Co), hafnium (Hf), lanthanum (La), nickel (Ni), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), indium (In), vanadium (V), silicon (S) and / or the corresponding oxides and / or the corresponding nitrides.

[0195] In Example 30a, the subject matter of any one of Examples 1a to 29a may optionally include: the first electrode layer and the second electrode layer having the same lateral dimension.

[0196] In Example 31a, the subject matter of any one of Examples 1a to 30a may optionally further include: at least one of the first electrode and the second electrode further includes a second functional layer in direct contact with the second electrode layer, and a third electrode layer in direct contact with the second functional layer, the third electrode layer having a third microstructure different from the second microstructure and the first microstructure.

[0197] In Example 32a, the subject matter of any of Examples 1a to 31a may optionally also include: the memory structure includes one or more residual polarization layers.

[0198] In Example 33a, the subject matter of Example 32a may optionally also include: the material of one or more residual polarization layers includes at least one of the following: hafnium oxide, zirconium oxide, or a mixture of hafnium oxide and zirconium oxide.

[0199] In Example 34a, the subject matter of any one of Examples 1a to 32a may optionally also include: a memory structure comprising one or more spontaneously polarized layers and one or more charge storage layers.

[0200] In Example 35a, the subject matter of any one of Examples 1a to 34a may optionally also include: a field-effect transistor structure, the field-effect transistor structure including a gate structure coupled to a memory capacitor.

[0201] In Example 36a, the subject matter of Example 35a may optionally also include: a memory capacitor coupled to a field-effect transistor structure to form a capacitive voltage divider.

[0202] In Example 37a, the subject matter of Example 35a or 36a may optionally also include: a gate structure of a field-effect transistor structure including a gate electrode and a gate isolation separating the gate electrode from the channel of the field-effect transistor, and the gate electrode being coupled to a first electrode of a memory capacitor.

[0203] In Example 38a, the subject matter of Example 37a may optionally also include: gate isolation extending from the channel region of the field-effect transistor structure to the gate electrode of the field-effect transistor structure.

[0204] In Example 39a, the subject matter of any one of Examples 35a to 38a may optionally also include: a field-effect transistor structure including a gate electrode layer, and a first electrode of a memory capacitor being spatially separated from and electrically connected to the gate electrode layer.

[0205] Example 1b is a memory cell comprising: a first electrode; a second electrode; and a memory structure disposed between the first electrode and the second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor, wherein at least one of the first electrode and the second electrode comprises: a first electrode layer; a functional layer in direct contact with the first electrode layer; and a second electrode layer in direct contact with the functional layer, wherein the functional layer is configured to reduce or prevent oxygen from diffusing from the second electrode layer into the first electrode layer.

[0206] In Example 2b, the subject matter of Example 1b may optionally also include: a first material of the first electrode layer comprising a first microstructure and a second material of the second electrode layer comprising a second microstructure different from the first microstructure, and the first microstructure differs from the second microstructure in at least one of the following aspects: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type and / or defect chemical composition.

[0207] In Example 3b, the subject matter of Example 1b or 2b may optionally further include: a first material of the first electrode layer comprising a plurality of grains having a first average grain size and / or a first grain size distribution, and a second material of the second electrode layer comprising a plurality of grains having a second average grain size and / or a second grain size distribution, wherein the first average grain size is different from the second average grain size and / or the first grain size distribution is different from the second grain size distribution.

[0208] In Example 4b, the subject matter of Example 3b may optionally also include: a second average particle size that is smaller than a first average particle size, or a second average particle size that is larger than a first average particle size.

[0209] In Example 5b, the subject matter of Example 3b or 4b may optionally include: a first particle size distribution that is wider than a second particle size distribution, or a first particle size distribution that is narrower than a second particle size distribution.

[0210] In Example 6b, the subject matter of any one of Examples 1b to 5b may optionally also include: the material of the memory structure comprises a plurality of grains, the average grain size of which is substantially equal to the average grain size of a plurality of grains of the second material of the second electrode layer, and the average grain size of the plurality of grains of the material of the memory structure is different from (e.g., less than or greater than) the average grain size of a plurality of grains of the first material of the first electrode layer.

[0211] In Example 7b, the subject matter of any one of Examples 1b to 6b may optionally further include: a first material of the first electrode layer having a first oxygen weight percentage, and a second material of the second electrode layer having a second oxygen weight percentage different from the first oxygen weight percentage.

[0212] In Example 8b, the subject of Example 7b may optionally also include: a first oxygen weight percentage is less than a second oxygen weight percentage, or a second oxygen weight percentage is greater than a first oxygen weight percentage.

[0213] In Example 9b, the subject matter of any one of Examples 1b to 8b may optionally further include: a first material of the first electrode layer comprising a first major component, and a second material of the second electrode layer comprising a second major component different from the first major component.

[0214] In Example 10b, the subject matter of Example 9b may optionally further include: a first material having a first chemical composition and a second material having a second chemical composition, wherein the first chemical composition differs from the second chemical composition in at least one aspect of the content and / or doping of the participating elements.

[0215] In Example 11b, the subject matter of any one of Examples 1b to 10b may optionally include: a first material of the first electrode layer having a first crystal structure (e.g., one or more first crystal structure properties), and a second material of the second electrode layer having a second crystal structure (e.g., one or more second crystal structure properties) different from the first crystal structure.

[0216] In Example 12b, the subject matter of any one of Examples 1b to 11b may optionally also include: the first material of the first electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0217] In Example 13b, the subject matter of any one of Examples 1b to 12b may optionally also include: the second material of the second electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0218] In Example 14b, the subject matter of any one of Examples 1b to 13b may optionally include: a first electrode layer having a first thickness, and a second electrode layer having a second thickness different from the first thickness.

[0219] In Example 15b, the subject of Example 14b may optionally also include: a first thickness less than a second thickness, or a first thickness greater than a second thickness.

[0220] In Example 16b, the subject matter of any of Examples 1b to 15b may optionally also include: the second electrode layer being configured to be closer to the memory structure relative to the first electrode layer.

[0221] In Example 17b, the subject matter of Example 16b may optionally also include: the memory structure and the second electrode layer being in direct physical contact with each other.

[0222] In Example 18b, the subject matter of any one of Examples 1b to 17b may optionally further include: the functional layer is the interface region between the first electrode layer and the second electrode layer, and includes the uppermost portion of the first electrode layer and the lowermost portion of the second electrode layer.

[0223] In Example 19b, the subject matter of any one of Examples 1b to 18b may optionally also include: the thickness of the first functional layer is in the range of about 0.1 nm to about 5 nm, for example less than 0.5 nm or less than 0.2 nm.

[0224] In Example 20b, the subject matter of any one of Examples 1b to 19b may optionally include: a first electrode layer having a first conductivity, and a second electrode layer having a second conductivity different from the first conductivity.

[0225] In Example 21b, the subject of Example 20b may optionally also include: the functional layer having a conductivity less than a first conductivity and less than a second conductivity.

[0226] In Example 22b, the subject matter of Example 20b or 21b may optionally also include: a second conductivity less than a first conductivity, or a second conductivity greater than a first conductivity.

[0227] In Example 23b, the subject matter of Example 22b may optionally also include: the second conductivity is less than half of the first conductivity, or the second conductivity is at least twice as large as the first conductivity.

[0228] In Example 24b, the subject matter of any one of Examples 1b to 23b may optionally also include: the functional layer is an oxygen absorption layer or an oxygen diffusion barrier layer.

[0229] In Example 25b, the subject matter of any one of Examples 1b to 24b may optionally further include: a first electrode layer having a first oxygen diffusivity, and a second electrode layer having a second oxygen diffusivity different from the first oxygen diffusivity.

[0230] In Example 26b, the subject matter of Example 25b may optionally also include: the functional layer having an oxygen diffusivity that is less than the first oxygen diffusivity and less than the second oxygen diffusivity.

[0231] In Example 27b, the subject matter of Embodiments 25b or 26b may optionally further include: a second oxygen diffusivity that is less than a first oxygen diffusivity, or a second oxygen diffusivity that is greater than a first oxygen diffusivity.

[0232] In Example 28b, the subject matter of Example 27b may optionally also include: the second oxygen diffusivity is less than half of the first oxygen diffusivity, or the second oxygen diffusivity is at least twice as large as the first oxygen diffusivity.

[0233] In Example 29b, the subject matter of any one of Examples 1b to 28b may optionally also include: the material of the functional layer includes at least one of oxides, nitrides or oxynitrides.

[0234] In some examples, the material of the functional layer may include at least one of the following: germanium (Ge), platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), cobalt (Co), hafnium (Hf), lanthanum (La), nickel (Ni), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), indium (In), vanadium (V), silicon (S) and / or the corresponding oxides and / or the corresponding nitrides.

[0235] In Example 30b, the subject matter of any one of Examples 1b to 29b may optionally also include: the first electrode layer and the second electrode layer having the same lateral dimension.

[0236] In Example 31b, the subject matter of any one of Examples 1b to 30b may optionally further include: at least one of the first electrode and the second electrode further includes a second functional layer in direct contact with the second electrode layer and a third electrode layer in direct contact with the second functional layer, the third electrode layer having a third microstructure different from the second microstructure and the first microstructure.

[0237] In Example 32b, the subject matter of any of Examples 1b to 31b may optionally also include: the memory structure includes one or more residual polarization layers.

[0238] In Example 33b, the subject matter of Example 32b may optionally also include: the material of one or more residual polarization layers includes at least one of the following: hafnium oxide, zirconium oxide, or a mixture of hafnium oxide and zirconium oxide.

[0239] In Example 34b, the subject matter of any of Examples 1b to 32b may optionally also include: a memory structure comprising one or more spontaneously polarized layers and one or more charge storage layers.

[0240] In Example 35b, the subject matter of any one of Examples 1b to 34b may optionally also include: a field-effect transistor structure, the field-effect transistor structure including a gate structure coupled to a memory capacitor.

[0241] In Example 36b, the subject matter of Example 35b may optionally also include: a memory capacitor coupled to a field-effect transistor structure to form a capacitive voltage divider.

[0242] In Example 37b, the subject matter of Example 35b or 36b may optionally also include: a gate structure of a field-effect transistor structure including a gate electrode and a gate isolation separating the gate electrode from the channel of the field-effect transistor, and the gate electrode being coupled to a first electrode of a memory capacitor.

[0243] In Example 38b, the subject matter of Example 37b may optionally also include: gate isolation extending from the channel region of the field-effect transistor structure to the gate electrode of the field-effect transistor structure.

[0244] In Example 39b, the subject matter of any one of Examples 35b to 38b may optionally also include: a field-effect transistor structure including a gate electrode layer, and a first electrode of a memory capacitor being spatially separated from and electrically connected to the gate electrode layer.

[0245] Example 1c is a memory cell comprising: a first electrode; a second electrode; and a memory structure disposed between the first electrode and the second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor. The memory structure includes at least one layer comprising an oxygen-containing material. At least one of the first electrode and the second electrode comprises: an electrode layer and a functional layer, the functional layer being in direct contact with the electrode layer and the at least one layer comprising the oxygen-containing material. The functional layer is configured to reduce or prevent oxygen diffusion from the at least one layer comprising the oxygen-containing material into the electrode layer.

[0246] In Example 2c, the subject matter of Example 1c may optionally also include: a first material of the first electrode layer comprising a first microstructure and a second material of the second electrode layer comprising a second microstructure different from the first microstructure, and the first microstructure differs from the second microstructure in at least one of the following aspects: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type and / or defect chemical composition.

[0247] In Example 3c, the subject matter of Example 1c or 2c may optionally further include: a first material of the first electrode layer comprising a plurality of grains having a first average grain size and / or a first grain size distribution, and a second material of the second electrode layer comprising a plurality of grains having a second average grain size and / or a second grain size distribution, wherein the first average grain size is different from the second average grain size and / or the first grain size distribution is different from the second grain size distribution.

[0248] In Example 4c, the subject matter of Example 3c may optionally also include: a second average particle size that is smaller than a first average particle size, or a second average particle size that is larger than a first average particle size.

[0249] In Example 5c, the subject matter of Example 3c or 4c may optionally include: a first particle size distribution that is wider than a second particle size distribution, or a first particle size distribution that is narrower than a second particle size distribution.

[0250] In Example 6c, the subject matter of any one of Examples 1c to 5c may optionally also include: the material of the memory structure comprises a plurality of grains, the average grain size of which is substantially equal to the average grain size of a plurality of grains of the second material of the second electrode layer, and the average grain size of the plurality of grains of the material of the memory structure is different from (e.g., less than or greater than) the average grain size of a plurality of grains of the first material of the first electrode layer.

[0251] In Example 7c, the subject matter of any one of Examples 1c to 6c may optionally further include: a first material of the first electrode layer having a first oxygen weight percentage, and a second material of the second electrode layer having a second oxygen weight percentage different from the first oxygen weight percentage.

[0252] In Example 8c, the subject of Example 7c may optionally also include: a first oxygen weight percentage being less than a second oxygen weight percentage, or a second oxygen weight percentage being greater than a first oxygen weight percentage.

[0253] In Example 9c, the subject matter of any one of Examples 1c to 8c may optionally further include: a first material of the first electrode layer comprising a first major component, and a second material of the second electrode layer comprising a second major component different from the first major component.

[0254] In Example 10c, the subject matter of Example 9c may optionally further include: a first material having a first chemical composition and a second material having a second chemical composition, wherein the first chemical composition differs from the second chemical composition in at least one aspect of the content and / or doping of the participating elements.

[0255] In Example 11c, the subject matter of any one of Examples 1c to 10c may optionally also include: a first material of the first electrode layer having a first crystal structure (e.g., one or more first crystal structure properties), and a second material of the second electrode layer having a second crystal structure (e.g., one or more second crystal structure properties) different from the first crystal structure.

[0256] In Example 12c, the subject matter of any one of Examples 1c to 11c may optionally also include: the first material of the first electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0257] In Example 13c, the subject matter of any one of Examples 1c to 12c may optionally also include: the second material of the second electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0258] In Example 14c, the subject matter of any one of Examples 1c to 13c may optionally include: a first electrode layer having a first thickness, and a second electrode layer having a second thickness different from the first thickness.

[0259] In Example 15c, the subject of Example 14c may optionally also include: a first thickness less than a second thickness, or a first thickness greater than a second thickness.

[0260] In Example 16c, the subject matter of any of Examples 1c to 15c may optionally also include: the second electrode layer being configured to be closer to the memory structure than the first electrode layer.

[0261] In Example 17c, the subject matter of Example 16c may optionally also include: the memory structure and the second electrode layer being in direct physical contact with each other.

[0262] In Example 18c, the subject matter of any one of Examples 1c to 17c may optionally further include: the functional layer is the interface region between the first electrode layer and the second electrode layer, and includes the uppermost portion of the first electrode layer and the lowermost portion of the second electrode layer.

[0263] In Example 19c, the subject matter of any one of Examples 1c to 18c may optionally further include: the thickness of the first functional layer being in the range of about 0.1 nm to about 5 nm, for example less than 0.5 nm or less than 0.2 nm.

[0264] In Example 20c, the subject matter of any one of Examples 1c to 19c may optionally include: a first electrode layer having a first conductivity, and a second electrode layer having a second conductivity different from the first conductivity.

[0265] In Example 21c, the subject of Example 20c may optionally also include: a functional layer having a conductivity less than a first conductivity and less than a second conductivity.

[0266] In Example 22c, the subject matter of Example 20c or 21c may optionally also include: a second conductivity less than a first conductivity, or a second conductivity greater than a first conductivity.

[0267] In Example 23c, the subject matter of Example 22c may optionally also include: the second conductivity is less than half of the first conductivity, or the second conductivity is at least twice as large as the first conductivity.

[0268] In Example 24c, the subject matter of any one of Examples 1c to 23c may optionally also include: the functional layer is an oxygen absorption layer or an oxygen diffusion barrier layer.

[0269] In Example 25c, the subject matter of any one of Examples 1c to 24c may optionally further include: a first electrode layer comprising a first oxygen diffusivity, and a second electrode layer comprising a second oxygen diffusivity different from the first oxygen diffusivity.

[0270] In Example 26c, the subject matter of Example 25c may optionally also include: the functional layer having an oxygen diffusivity that is less than a first oxygen diffusivity and less than a second oxygen diffusivity.

[0271] In Example 27c, the subject matter of Embodiments 25c or 26c may optionally further include: a second oxygen diffusivity that is less than a first oxygen diffusivity, or a second oxygen diffusivity that is greater than a first oxygen diffusivity.

[0272] In Example 28c, the subject matter of Example 27c may optionally also include: the second oxygen diffusivity is less than half of the first oxygen diffusivity, or the second oxygen diffusivity is at least twice as large as the first oxygen diffusivity.

[0273] In Example 29c, the subject matter of any one of Examples 1c to 28c may optionally also include: the material of the functional layer includes at least one of oxides, nitrides or oxynitrides.

[0274] In some examples, the material of the functional layer may include at least one of the following: germanium (Ge), platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), cobalt (Co), hafnium (Hf), lanthanum (La), nickel (Ni), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), indium (In), vanadium (V), silicon (S) and / or the corresponding oxides and / or the corresponding nitrides.

[0275] In Example 30c, the subject matter of any one of Examples 1c to 29c may optionally also include: the first electrode layer and the second electrode layer having the same lateral dimension.

[0276] In Example 31c, the subject matter of any one of Examples 1c to 30c may optionally further include: at least one of the first electrode and the second electrode further includes a second functional layer in direct contact with the second electrode layer and a third electrode layer in direct contact with the second functional layer, the third electrode layer having a third microstructure different from the second microstructure and the first microstructure.

[0277] In Example 32c, the subject matter of any of Examples 1c to 31c may optionally also include: the memory structure includes one or more residual polarization layers.

[0278] In Example 33c, the subject matter of Example 32c may optionally also include: the material of one or more residual polarization layers includes at least one of the following: hafnium oxide, zirconium oxide, or a mixture of hafnium oxide and zirconium oxide.

[0279] In Example 34c, the subject matter of any of Examples 1c to 32c may optionally also include: a memory structure comprising one or more spontaneously polarized layers and one or more charge storage layers.

[0280] In Example 35c, the subject matter of any one of Examples 1c to 34c may optionally also include: a field-effect transistor structure, the field-effect transistor structure including a gate structure coupled to a memory capacitor.

[0281] In Example 36c, the subject matter of Example 35c may optionally also include: a memory capacitor coupled to a field-effect transistor structure to form a capacitive voltage divider.

[0282] In Example 37c, the subject matter of Example 35c or 36c may optionally also include: a gate structure of a field-effect transistor structure including a gate electrode and a gate isolation separating the gate electrode from the channel of the field-effect transistor, and the gate electrode being coupled to a first electrode of a memory capacitor.

[0283] In Example 38c, the subject matter of Example 37c may optionally also include: gate isolation extending from the channel region of the field-effect transistor structure to the gate electrode of the field-effect transistor structure.

[0284] In Example 39c, the subject matter of any one of Examples 35c to 38c may optionally also include: a field-effect transistor structure including a gate electrode layer, and a first electrode of a memory capacitor being spatially separated from and electrically connected to the gate electrode layer.

[0285] Example 1d is a memory cell comprising: a first electrode; a second electrode; and a memory structure disposed between the first electrode and the second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor, wherein at least one of the first electrode and the second electrode comprises: a first electrode layer having a first conductivity; a functional layer in direct contact with the first electrode layer; and a second electrode layer in direct contact with the functional layer, the second electrode layer having a second conductivity less than the first conductivity.

[0286] In Example 2d, the subject matter of Example 1d may optionally also include: a first material of the first electrode layer comprising a first microstructure and a second material of the second electrode layer comprising a second microstructure different from the first microstructure, and the first microstructure differs from the second microstructure in at least one of the following aspects: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type and / or defect chemical composition.

[0287] In Example 3d, the subject matter of Example 1d or 2d may optionally further include: a first material of the first electrode layer comprising a plurality of grains having a first average grain size and / or a first grain size distribution, and a second electrode layer of the second material comprising a plurality of grains having a second average grain size and / or a second grain size distribution, wherein the first average grain size differs from the second average grain size and / or the first grain size distribution differs from the second grain size distribution. In some aspects, the first material of the first electrode layer comprises a first crystalline texture, and the second material of the second electrode layer comprises a second crystalline texture different from the first crystalline texture.

[0288] In Example 4d, the subject of Example 3d may optionally also include: a second average particle size that is smaller than a first average particle size, or a second average particle size that is larger than a first average particle size.

[0289] In Example 5d, the subject of Example 3d or 4d may optionally also include: a first particle size distribution that is wider than a second particle size distribution, or a first particle size distribution that is narrower than a second particle size distribution.

[0290] In Example 6d, the subject matter of any one of Examples 1d to 5d may optionally also include: the material of the memory structure comprises a plurality of grains, the average grain size of which is substantially equal to the average grain size of a plurality of grains of the second material of the second electrode layer, and the average grain size of the plurality of grains of the material of the memory structure is different from (e.g., less than or greater than) the average grain size of a plurality of grains of the first material of the first electrode layer.

[0291] In Example 7d, the subject matter of any one of Examples 1d to 6d may optionally also include: a first material of the first electrode layer having a first oxygen weight percentage, and a second material of the second electrode layer having a second oxygen weight percentage different from the first oxygen weight percentage.

[0292] In Example 8d, the subject of Example 7d may optionally also include: a first oxygen weight percentage less than a second oxygen weight percentage, or a second oxygen weight percentage greater than a first oxygen weight percentage.

[0293] In Example 9d, the subject matter of any one of Examples 1d to 8d may optionally also include: a first material of the first electrode layer comprising a first major component, and a second material of the second electrode layer comprising a second major component different from the first major component.

[0294] In Example 10d, the subject matter of Example 9d may optionally also include: a first material having a first chemical composition and a second material having a second chemical composition, wherein the first chemical composition differs from the second chemical composition in at least one aspect of the content and / or doping of the participating elements.

[0295] In Example 11d, the subject matter of any one of Examples 1d to 10d may optionally also include: a first material of the first electrode layer having a first crystal structure (e.g., one or more first crystal structure properties), and a second material of the second electrode layer having a second crystal structure (e.g., one or more second crystal structure properties) different from the first crystal structure.

[0296] In Example 12d, the subject matter of any one of Examples 1d to 11d may optionally also include: the first material of the first electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0297] In Example 13d, the subject matter of any one of Examples 1d to 12d may optionally also include: the second material of the second electrode layer includes at least one of the following: platinum, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, gold, cobalt.

[0298] In Example 14d, the subject matter of any one of Examples 1d to 13d may optionally also include: a first electrode layer having a first thickness, and a second electrode layer having a second thickness different from the first thickness.

[0299] In Example 15d, the subject of Example 14d may optionally also include: a first thickness less than a second thickness, or a first thickness greater than a second thickness.

[0300] In Example 16d, the subject matter of any one of Examples 1d to 15d may optionally also include: the second electrode layer being configured to be closer to the memory structure than the first electrode layer.

[0301] In Example 17d, the subject matter of Example 16d may optionally also include: the memory structure and the second electrode layer being in direct physical contact with each other.

[0302] In Example 18d, the subject matter of any one of Examples 1d to 17d may optionally also include: the functional layer is the interface region between the first electrode layer and the second electrode layer, and includes the uppermost part of the first electrode layer and the lowermost part of the second electrode layer.

[0303] In Example 19d, the subject matter of any one of Examples 1d to 18d may optionally also include: the thickness of the first functional layer is in the range of about 0.1 nm to about 5 nm, for example less than 0.5 nm or less than 0.2 nm.

[0304] In Example 20d, the subject matter of any one of Examples 1d to 19d may optionally also include: the functional layer having a conductivity less than a first conductivity and less than a second conductivity.

[0305] In Example 21d, the subject matter of Example 20d may optionally also include: the functional layer having a conductivity at least 10 orders of magnitude smaller than the first conductivity and at least 10 orders of magnitude smaller than the second conductivity.

[0306] In Example 22d, the subject matter of Example 20d or 21d may optionally also include: the second conductivity is less than half of the first conductivity.

[0307] In Example 23d, the subject matter of any one of Examples 1d to 22d may optionally also include: the second conductivity is an order of magnitude smaller than the first conductivity.

[0308] In Example 24d, the subject of any of Examples 1d to 23d may optionally also include: the functional layer is an oxygen absorption layer or an oxygen diffusion barrier layer.

[0309] In Example 25d, the subject matter of any one of Examples 1d to 24d may optionally further include: a first electrode layer comprising a first oxygen diffusivity, and a second electrode layer comprising a second oxygen diffusivity different from the first oxygen diffusivity.

[0310] In Example 26d, the subject of Example 25d may optionally also include: the functional layer having an oxygen diffusivity that is less than the first oxygen diffusivity and less than the second oxygen diffusivity.

[0311] In Example 27d, the subject matter of Example 25d or 26d may optionally also include: a second oxygen diffusivity that is less than a first oxygen diffusivity, or a second oxygen diffusivity that is greater than a first oxygen diffusivity.

[0312] In Example 28d, the subject matter of Example 27d may optionally also include: the second oxygen diffusivity is less than half of the first oxygen diffusivity, or the second oxygen diffusivity is at least twice as large as the first oxygen diffusivity.

[0313] In Example 29d, the subject matter of any one of Examples 1d to 28d may optionally also include: the material of the functional layer includes at least one of oxides, nitrides or oxynitrides.

[0314] In some examples, the material of the functional layer may include at least one of the following: germanium (Ge), platinum (Pt), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), titanium (Ti), osmium (Os), molybdenum (Mo), chromium (Cr), tungsten (W), aluminum (Al), gold (Au), cobalt (Co), hafnium (Hf), lanthanum (La), nickel (Ni), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), indium (In), vanadium (V), silicon (S) and / or the corresponding oxides and / or the corresponding nitrides.

[0315] In Example 30d, the subject matter of any one of Examples 1d to 29d may optionally also include: the first electrode layer and the second electrode layer having the same lateral dimension.

[0316] In Example 31d, the subject matter of any one of Examples 1d to 30d may optionally further include: at least one of the first electrode and the second electrode further includes a second functional layer in direct contact with the second electrode layer and a third electrode layer in direct contact with the second functional layer, the third electrode layer having a third microstructure different from the second microstructure and the first microstructure.

[0317] In Example 32d, the subject matter of any of Examples 1d to 31d may optionally also include: the memory structure includes one or more residual polarization layers.

[0318] In Example 33d, the subject matter of Example 32d may optionally also include: the material of one or more residual polarization layers includes at least one of the following: hafnium oxide, zirconium oxide, or a mixture of hafnium oxide and zirconium oxide.

[0319] In Example 34d, the subject matter of any of Examples 1d to 32d may optionally also include: a memory structure comprising one or more spontaneously polarized layers and one or more charge storage layers.

[0320] In Example 35d, the subject matter of any one of Examples 1d to 34d may optionally also include: a field-effect transistor structure, the field-effect transistor structure including a gate structure coupled to a memory capacitor.

[0321] In Example 36d, the subject matter of Example 35d may optionally also include: a memory capacitor coupled to a field-effect transistor structure to form a capacitive voltage divider.

[0322] In Example 37d, the subject matter of Example 35d or 36d may optionally also include: a gate structure of a field-effect transistor structure including a gate electrode and a gate isolation separating the gate electrode from the channel of the field-effect transistor, and the gate electrode being coupled to a first electrode of a memory capacitor.

[0323] In Example 38d, the subject matter of Example 37d may optionally also include: gate isolation extending from the channel region of the field-effect transistor structure to the gate electrode of the field-effect transistor structure.

[0324] In Example 39d, the subject matter of any one of Examples 35d to 38d may optionally also include: a field-effect transistor structure including a gate electrode layer, and a first electrode of a memory capacitor being spatially separated from and electrically connected to the gate electrode layer.

[0325] Example 1e is a method of forming a memory capacitor, comprising: forming a first electrode; forming a memory structure in direct contact with the first electrode; and forming a second electrode in direct contact with the memory structure, wherein forming the first electrode and forming the second electrode comprises forming a first electrode layer using first process parameters and forming the second electrode layer using second process parameters different from the first process parameters.

[0326] In Example 2e, the subject matter of Example 1e may optionally also include: the first process parameter differs from the second process parameter in at least one of the following aspects: processing temperature, processing pressure, precursor material, process gas (e.g., process gas flow) and / or partial pressure of the process gas.

[0327] In Example 3e, the subject matter of Example 1e or 2e may optionally also include: a first processing temperature under which the first electrode layer is formed differs from a second processing temperature under which the second electrode layer is formed by at least 5% or at least 50%.

[0328] In Example 4e, the subject matter of any one of Examples 1e to 3e may optionally also include: a first processing pressure under which the first electrode layer is formed differs from a second processing pressure under which the second electrode layer is formed by at least 5% or at least 50%.

[0329] In Example 5e, the subject matter of any one of Examples 1e to 4e may optionally also include: the first precursor material for forming the first electrode layer is different from the second precursor material for forming the second electrode layer in at least one of the following aspects: the electrical conductivity, chemical composition and / or content of the participating elements.

[0330] In Example 6e, the subject matter of any one of Examples 1e to 5e may optionally also include: the first process gas used to form the first electrode layer is different from the second process gas used to form the second electrode layer in at least one of the following aspects: the chemical composition and / or content of the participating elements.

[0331] In Example 7e, the subject matter of any one of Examples 1e to 6e may optionally include: the first oxygen amount used to form the first electrode layer differs from the second oxygen amount used to form the second electrode layer by at least 5% or at least 50%.

[0332] In Example 8e, the subject matter of any one of Examples 1e to 7e may optionally also include: the first oxygen partial pressure used during the formation of the first electrode layer differs from the second oxygen partial pressure used during the formation of the second electrode layer by at least 5% or at least 50%.

[0333] In Example 9e, the subject matter of any one of Examples 1e to 8e may optionally also include: waiting for a predetermined waiting time after the formation of the first electrode layer and before the formation of the second electrode layer.

[0334] In Example 10e, the subject of Example 9e may optionally also include: a scheduled waiting time of more than 1 minute.

[0335] In Example 11e, the subject matter of any one of Examples 1e to 10e may optionally include: forming a functional layer in direct contact with the first electrode layer before forming the second electrode layer, and forming a second electrode layer in direct contact with the functional layer.

[0336] In Example 12e, the subject matter of Example 11e may optionally also include: the functional layer is configured to affect one or more properties of the second electrode layer during the formation of the second electrode layer.

[0337] In Example 13e, the subject matter of any one of Examples 1e to 12e may optionally also include: forming a memory structure in direct contact with the second electrode layer, wherein the second electrode layer is configured to influence the characteristics of the memory structure during the formation of the memory structure.

[0338] Example 1f is a method of forming a memory capacitor, comprising: forming a first electrode; forming a memory structure in direct contact with the first electrode, the memory structure including at least one layer including an oxygen-containing material; and forming a second electrode in direct contact with the memory structure, wherein forming the first electrode and forming the second electrode includes forming an electrode layer and a functional layer in direct contact with the oxygen-containing material, wherein the functional layer is configured to reduce or prevent oxygen from diffusing from the at least one layer including the oxygen-containing material into the electrode layer.

[0339] Where appropriate, the method according to Example 1f may include one or more or each of the features described with respect to the methods according to Examples 1e to 13e.

[0340] Understandably, the physical term "electrical conductivity" (also known as, for example, specific conductivity or specific electrical conductivity) can be defined as a material-based property that is the reciprocal of the physical term "resistivity" (also known as, for example, specific resistance, volume resistivity). Other properties of layers or structures can be defined as material-dependent and geometry-dependent, for example, by the physical terms "resistance" and "electrical conductivity".

[0341] It is understood that the physical properties “average particle size” and / or “particle size distribution” can be determined based on various measurements and / or calculations. For example, the volume-weighted average particle size can be determined by known formulas. In some aspects, the average particle size can be determined by a known linear intercept method. Preferably, it can be measured according to ASTM E1382 (e.g., effective since 2015). However, in thin layers, such as layers less than 1 μm thick, TEM cross-sectional images can be used as the basis for determining the “average particle size” and / or “particle size distribution” in at least two dimensions. This two-dimensional determination allows for the estimation or inference of three-dimensional properties, for example, assuming that the two-dimensional image (statistically) represents essentially all directions in the layer. It is understood that the term “particle size distribution” can define a spatial distribution, such as a distribution along a line, plane, or volume. It is understood that the term “particle size distribution” can define a frequency distribution, such as a histogram including the number of grains with a specific range of particle sizes.

[0342] Understandably, the term "grain boundary density" can be defined by the number of grain boundaries per volume and / or by the volume fraction of the grain boundary volume compared to a reference volume.

[0343] It is understandable that the term "grain boundary chemical composition" can be interpreted as meaning that grain boundaries may include a different material than the corresponding grains. For example, the oxygen content in a grain boundary may differ from the oxygen content of the actual corresponding grain.

[0344] It is understood that the term "defective chemical composition" can be interpreted as defects including impurities. For example, the material that causes the impurity may have a chemical composition different from that of the material surrounding the impurity.

[0345] It is understood that a particular type of crystallinity in a material can be a microstructural property. As an example, the types of crystallinity can include, for example, single crystals, polycrystalline, nanocrystalline, and, as an edge case, amorphous structures.

[0346] Various aspects involve adjusting or controlling the microstructural properties of the material. Crystalline texture is a microstructural property that can be controlled during electrode formation and / or by selecting a suitable design for the electrode (e.g., a multilayer design). Depending on the aspects, the texture of the top electrode layer can be produced by forming several consecutive electrode layers, as described herein.

[0347] The term "metallic material" may be used herein to describe metals (e.g., pure metals or essentially pure metals), mixtures of more than one metal, metal alloys, intermetallic materials, conductive metal compounds (e.g., nitrides), etc. Illustratively, the term "metallic material" may be used herein to describe materials that are conductive (typically metals), for example, having a conductivity greater than 10 at a temperature of 20°C. 5 S / m. The term "metallic material" may be used herein to describe materials having a Fermi level in at least one band.

[0348] The terms “conductive” or “electrically conductive” are used interchangeably herein to describe a substance having a conductivity greater than 10 ohms at a temperature of 20°C. 5 The electrical conductivity or average conductivity is measured in S / m. The terms "electrical insulation" or "electrical isolation" are used interchangeably herein to describe materials or layers having an electrical conductivity of less than 10 S / m at a temperature of 20°C. -7 The conductivity or average conductivity of the material or layer is S / m. In some aspects, at a temperature of 20°C, the difference in conductivity between the conductive material (or layer) and the electrically insulating material (or layer) may have a value of at least 10. 10 S / m or at least 10 12 The absolute value of S / m.

[0349] In some respects, the term "content" may be used herein with respect to the "elemental content" in a material or layer to describe the mass percentage (or fraction) of that element in the total mass of the material (or layer). The term "content" may also be used herein with respect to the "defect content" in a material structure to describe the mass percentage of defects in the total mass of the structural components. In some respects, the term "content" may also be used herein with respect to the "elemental content" in a material or layer to describe the volume percentage of that element in the total volume of the material (layer). The term "content" may also be used herein with respect to the "defect content" in a material structure to describe the volume percentage of defects in the total volume of the structure.

[0350] The term "material of a layer," such as "material of an electrode layer" or "material of a functional layer," can be used herein to describe the main components of the layer, such as the main material present in the layer (e.g., a main element or a main compound). In some aspects, the term "material of a layer" may describe a layer comprising more than 60% by weight of the material comprising the layer. In some aspects, the term "material of a layer" may describe a layer comprising more than 60% by volume of the material comprising the layer. As an example, the material of a layer comprising aluminum may describe that the layer is primarily formed of aluminum, and other elements (e.g., impurities) may be present in a smaller proportion, such as having a smaller weight percentage or a smaller volume percentage compared to aluminum. As another example, the material of a layer comprising titanium nitride may describe that the layer is primarily formed of titanium nitride, and other elements (e.g., impurities) may be present in a smaller proportion, such as having a smaller weight percentage or a smaller volume percentage compared to titanium nitride.

[0351] Depending on various aspects, the characteristics (e.g., physical properties, chemical properties, etc.) of the first component (e.g., element, layer, structure, part, etc.) of the second component can be compared with each other. It can be found that, with respect to a particular characteristic, two or more components may be the same as or different from each other. As a measure, values ​​representing such characteristics may be equal or unequal. Generally, a person skilled in the art can understand from the context of the application whether two values ​​or characteristics are equal; for example, generally, if the values ​​are within the usual tolerance range, these values ​​can be considered equal. However, in some aspects, or unless otherwise mentioned or understood, two values ​​having a relative difference of at least 1% can be considered different from each other. Therefore, two values ​​having a relative difference of less than 1% can be considered equal to each other.

[0352] While the invention has been specifically shown and described with reference to specific aspects thereof, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the scope of the invention is indicated by the appended claims and is thus intended to cover all variations falling within the meaning and scope of equivalents of the claims.

Claims

1. A memory cell, comprising: First electrode; Second electrode; as well as A memory structure is disposed between the first electrode and the second electrode. The first electrode, the second electrode, and the memory structure form a memory capacitor, wherein at least one of the first electrode and the second electrode includes: A first electrode layer, the first electrode layer comprising a first material having a first microstructure, the first microstructure comprising a plurality of grains having a first average grain size, a first crystal texture and / or a first grain size distribution; A functional layer, wherein the functional layer is in direct contact with the first electrode layer; and The second electrode layer is in direct contact with the functional layer. The second electrode layer includes a second material having a second microstructure different from the first microstructure, for reducing the leakage current of the memory capacitor. The second microstructure includes a plurality of grains having a second average particle size different from the first average particle size, a second crystal texture different from the first crystal texture, and / or a second particle size distribution different from the first particle size distribution.

2. The memory unit according to claim 1, in, The first microstructure differs from the second microstructure in at least one of the following aspects: grain size, average grain size, grain size distribution, number of grain boundaries, grain boundary space density, grain boundary shape, grain boundary chemical composition, region between two adjacent grains, defect content, defect type, crystal texture and / or defect chemical composition.

3. The memory unit according to claim 1, in, The first material of the first electrode layer has a first oxygen weight percentage, and the second material of the second electrode layer has a second oxygen weight percentage different from the first oxygen weight percentage.

4. The memory unit according to claim 1, in, The first material of the first electrode layer includes a first major component, and the second material of the second electrode layer includes a second major component that is different from the first major component.

5. The memory unit according to claim 4, in, The first material has a first chemical composition and the second material has a second chemical composition, wherein the first chemical composition differs from the second chemical composition in at least one aspect of the content and / or doping of the participating elements.

6. The memory unit according to claim 1, in, The first material of the first electrode layer has a first crystal structure, and the second material of the second electrode layer has a second crystal structure different from the first crystal structure.

7. The memory unit according to claim 1, in, The first material of the first electrode layer includes at least one of the following: platinum, tantalum, indium, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, and cobalt.

8. The memory unit according to claim 1, in, The second material of the second electrode layer includes at least one of the following: platinum, tantalum, indium, iridium, rhenium, rhodium, ruthenium, titanium, osmium, molybdenum, chromium, tungsten, aluminum, and cobalt.

9. The memory unit according to claim 1, in, The first electrode layer has a first thickness, and the second electrode layer has a second thickness different from the first thickness.

10. The memory unit according to claim 1, in, The second electrode layer is configured to be closer to the memory structure than the first electrode layer.

11. The memory cell according to claim 1, in, The first electrode layer has a first conductivity, and the second electrode layer has a second conductivity that is different from the first conductivity.

12. The memory cell according to claim 1, in, The functional layer is an oxygen absorption layer or an oxygen diffusion barrier layer.

13. The memory cell according to claim 1, in, The first electrode layer has a first oxygen diffusivity, and the second electrode layer has a second oxygen diffusivity that is different from the first oxygen diffusivity.

14. The memory cell according to claim 1, in, At least one of the first electrode and the second electrode further includes: a second functional layer in direct contact with the second electrode layer; and a third electrode layer in direct contact with the second functional layer, the third electrode layer having a third microstructure that is different from the second microstructure and different from the first microstructure.

15. The memory cell according to claim 1, in, The memory structure includes one or more residual polarization layers.

16. A memory cell, comprising: First electrode; Second electrode; as well as A memory structure is disposed between a first electrode and a second electrode, the first electrode, the second electrode, and the memory structure forming a memory capacitor, wherein at least one of the first electrode and the second electrode includes: A first electrode layer having a first conductivity, the first electrode layer comprising a first material having a first microstructure, the first microstructure comprising a plurality of grains having a first average grain size, a first crystal texture and / or a first grain size distribution; A functional layer, wherein the functional layer is in direct contact with the first electrode layer; and The second electrode layer is in direct contact with the functional layer. The second electrode layer has a second conductivity that is less than the first conductivity. The second electrode layer includes a second material having a second microstructure that is different from the first microstructure, for reducing the leakage current of the memory capacitor. The second microstructure includes a plurality of grains having a second average grain size that is different from the first average grain size, a second crystal texture that is different from the first crystal texture, and / or a second grain size distribution that is different from the first grain size distribution.

17. The memory cell according to claim 16, in, The first conductivity is at least twice as great as the second conductivity.

18. A method of forming a memory capacitor, the method comprising: Form the first electrode; A memory structure is formed that is in direct contact with the first electrode; as well as A second electrode is formed that is in direct contact with the memory structure. Wherein, forming at least one of the first electrode and forming the second electrode includes forming a first electrode layer using a first process parameter and forming a second electrode layer using a second process parameter different from the first process parameter; Wherein, the first electrode layer includes a first material having a first microstructure, the first microstructure including a plurality of grains having a first average grain size, a first crystal texture and / or a first grain size distribution; The second electrode layer includes a second material having a second microstructure different from the first microstructure, for reducing the leakage current of the memory capacitor, wherein the second microstructure includes a plurality of grains having a second average grain size different from the first average grain size, a second crystal texture different from the first crystal texture, and / or a second grain size distribution different from the first grain size distribution; The method further includes: A functional layer is formed, which is in direct contact with the first electrode layer, and the second electrode layer is in direct contact with the functional layer.

19. The method according to claim 18, in, The first process parameter differs from the second process parameter in at least one of the following aspects: processing temperature, processing pressure, precursor material, process gas and / or partial pressure of process gas.

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