CBRAM device based on Ti-Cu alloy electrode and preparation method thereof

Abstract

The invention provides a CBRAM device based on a Ti-Cu alloy electrode and a preparation method of the CBRAM device. The CBRAM device based on the Ti-Cu alloy electrode comprises a substrate, a first electrode, a resistive layer and a second electrode, wherein the first electrode and the second electrode are made of an active electrode material or an inert electrode material, and when the first electrode is made of the active electrode material, the second electrode is made of the inert electrode material; when the material of the first electrode is an inert electrode material, the material of the second electrode is an active electrode material; the material of the active electrode is Ti-Cu alloy, and the Ti-Cu alloy electrode is used for replacing a Cu electrode, so that the number of Cu atoms which are injected from the electrode and form the conductive filament is limited, and the durability of the CBRAM device can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic integrated circuits, and particularly to a CBRAM device based on a Ti-Cu alloy electrode and a preparation method thereof. Background Art

[0002] With the rapid development of information technology, the demand for memories is increasing continuously. As a new type of non-volatile memory, RRAM has attracted much attention due to its advantages such as fast read and write speeds, high density, and low power consumption. As a kind of RRAM, CBRAM (conductive-bridging random-access memory) realizes data storage by forming a conductive bridge between electrodes. CBRAM generally has a sandwich structure, in which one end often uses an active electrode such as Cu or Ag, the other end uses an inert electrode such as Pt or TiN, and the middle switching layer is a solid electrolyte, often using an oxide or a sulfide. Under the action of an electric field, with the formation and breakage of the conductive bridge, the device exhibits a switching of resistance states.

[0003] Although CBRAM devices perform well in some aspects, they have certain limitations in terms of long-term durability and the like. Therefore, based on the technical disadvantages of current CBRAM devices, it is necessary to improve them.

[0004] Based on the disadvantages of current pure metal electrode-based CBRAM devices, it is necessary to improve them. Summary of the Invention

[0005] In view of the above-mentioned disadvantages or improvement requirements of the prior art, the present invention provides a CBRAM device based on a Ti-Cu alloy electrode and a preparation method thereof to solve the problem of low long-term durability of existing CBRAM devices.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a CBRAM device based on a Ti-Cu alloy electrode, including:

[0008] A substrate;

[0009] A first electrode located on the surface of the substrate;

[0010] A resistive switching layer located on the surface of the first electrode away from the substrate;

[0011] A second electrode arrayed on the surface of the resistive switching layer away from the substrate;

[0012] Among them, the materials of the first electrode and the second electrode are active electrode materials or inert electrode materials. When the material of the first electrode is an active electrode material, the material of the second electrode is an inert electrode material; when the material of the first electrode is an inert electrode material, the material of the second electrode is an active electrode material;

[0013] The active electrode material is a Ti-Cu alloy.

[0014] Preferably, the mass fraction of Cu in the Ti-Cu alloy is 22-99%, and the balance is Ti.

[0015] Preferably, the inert electrode material includes at least one of Ti, Pt, W, and TiN;

[0016] The material of the resistive switching layer includes any one of hafnium oxide, silicon oxide, zirconium oxide, germanium telluride, and germanium selenide.

[0017] Preferably, the substrate includes any one of a Si / SiO2 / Ti substrate, a Si substrate, a SiO2 substrate, a c-plane sapphire substrate, a magnesium oxide substrate, a gallium oxide substrate, a gallium nitride substrate, an NSTO substrate, a quartz glass substrate, an r-plane sapphire substrate, and an a-plane sapphire substrate.

[0018] Preferably, the shape of the second electrode is rectangular or circular. The side length of the rectangle is 10 nm to 10 mm, and the diameter of the circle is 10 nm to 10 mm.

[0019] Preferably, the thickness of the first electrode is 10-900 nm;

[0020] The thickness of the resistive switching layer is 1-800 nm;

[0021] The thickness of the second electrode is 10-900 nm.

[0022] In a second aspect, the present invention also provides a method for manufacturing the above-mentioned CBRAM device based on a Ti-Cu alloy electrode, including the following steps:

[0023] Prepare a first electrode on the surface of the substrate;

[0024] Prepare a resistive switching layer on the surface of the first electrode;

[0025] Prepare an array of second electrodes on the surface of the resistive switching layer.

[0026] Preferably, the method for preparing the Ti-Cu alloy includes: using a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2-0.8 Pa, the sputtering power of Cu is 1-40 W, the sputtering time of Cu is 180-6000 s, the sputtering power of Ti is 1-40 W, and the sputtering time of Ti is 180-6000 s.

[0027] Preferably, the first electrode is prepared by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2-0.8 Pa, the sputtering power is 1-40 W, and the sputtering time is 180-6000 s. Preferably, the resistive switching layer is prepared by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2-0.8 Pa, the sputtering power is 1-60 W, and the sputtering time is 100-7000 s.

[0028] The CBRAM device based on the Ti-Cu alloy electrode and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0029] The CBRAM device based on the Ti-Cu alloy electrode of the present invention includes a substrate, a first electrode, a resistive switching layer, and a second electrode; among them, the materials of the first electrode and the second electrode are active electrode materials or inert electrode materials. When the material of the first electrode is an active electrode material, the material of the second electrode is an inert electrode material; when the material of the first electrode is an inert electrode material, the material of the second electrode is an active electrode material; the active electrode material is a Ti-Cu alloy. Using a Ti-Cu alloy electrode to replace the Cu electrode limits the number of Cu atoms forming conductive filaments injected from the electrode, and can greatly improve the durability of the CBRAM device. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic structural diagram of the CBRAM device based on the Ti-Cu alloy electrode of the present invention;

[0032] Figure 2 It is the I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 1;

[0033] Figure 3It is the resistance state distribution diagram of the CBRAM device based on the Ti-Cu electrode in Example 1;

[0034] Figure 4 It is the I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 2;

[0035] Figure 5 It is the resistance state distribution diagram of the CBRAM device based on the Ti-Cu alloy electrode prepared in Example 2;

[0036] Figure 6 It is the I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 3;

[0037] Figure 7 It is the resistance state distribution diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 3;

[0038] Figure 8 It is the I-V curve diagram of the CBRAM device based on the Cu alloy electrode prepared in Comparative Example 1;

[0039] Figure 9 It is the resistance state distribution diagram of the CBRAM device based on the Cu alloy electrode in Comparative Example 1;

[0040] Figure 10 It is the I-V curve diagram of the OxRAM device based on the Ti electrode in Comparative Example 2;

[0041] Figure 11 It is the resistance state distribution diagram of the OxRAM device based on the Ti electrode in Comparative Example 2.

[0042] Figure 12 It is the XPS analysis diagram of the Cu element in the Ti-Cu alloy electrode prepared in Example 2;

[0043] Figure 13 It is the XPS analysis diagram of the Ti element in the Ti-Cu alloy electrode prepared in Example 2;

[0044] Figure 14 It is the XPS analysis diagram of the Cu element in the Ti-Cu alloy electrode prepared in Example 3;

[0045] Figure 15 It is the XPS analysis diagram of the Ti element in the Ti-Cu alloy electrode prepared in Example 3. Detailed implementation manners

[0046] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper" is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0048] The description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0049] The embodiments of this application provide a CBRAM device based on a Ti-Cu alloy electrode, as Figure 1 shown, including:

[0050] Substrate 1;

[0051] The first electrode 2, which is located on the surface of the substrate 1;

[0052] The resistive switching layer 3, which is located on the surface of the first electrode 2 away from the substrate 1;

[0053] The second electrode 4, which is arranged in an array on the surface of the resistive switching layer 3 away from the substrate 1;

[0054] The materials of the first electrode 2 and the second electrode 4 are active electrode materials or inert electrode materials. When the material of the first electrode 2 is an active electrode material, the material of the second electrode 4 is an inert electrode material; when the material of the first electrode 2 is an inert electrode material, the material of the second electrode 4 is an active electrode material;

[0055] The active electrode material is a Ti-Cu alloy.

[0056] The CBRAM device based on the Ti-Cu alloy electrode of the present invention includes a substrate 1, a first electrode 2, a resistive switching layer 3, and a second electrode 4; wherein, the substrate 1, the first electrode 2, and the resistive switching layer 3 are sequentially stacked; the second electrode 4 is arranged in an array on the surface of the resistive switching layer 3 away from the substrate 1; the positions of the first electrode 2 and the second electrode 4 can be interchanged, and the materials of the first electrode 2 and the second electrode 4 are active electrode materials or inert electrode materials. When the material of the first electrode 2 is an active electrode material, the material of the second electrode 4 is an inert electrode material; when the material of the first electrode 2 is an inert electrode material, the material of the second electrode 4 is an active electrode material; that is, when the first electrode 2 is an active electrode, the second electrode 4 is an inert electrode, and when the first electrode 2 is an inert electrode, the second electrode 4 is an active electrode; specifically, the material of the active electrode is a Ti-Cu alloy. Using a Ti-Cu alloy electrode to replace the Cu electrode limits the number of Cu atoms forming conductive filaments injected from the electrode, and can greatly improve the durability of the CBRAM device.

[0057] In some embodiments, the mass fraction of Cu in the Ti-Cu alloy is 22-99%, and the balance is Ti (i.e., the mass fraction of Ti is 78-1%).

[0058] In some embodiments, the inert electrode material includes at least one of inert electrode materials such as Ti, Pt, W, TiN (titanium nitride), etc.

[0059] In some embodiments, the material of the resistive switching layer 3 includes any one of hafnium oxide, silicon oxide, and zirconium oxide.

[0060] In some embodiments, the substrate 1 includes any one of a Si / SiO2 / Ti substrate, a Si substrate, a SiO2 substrate, a c-plane sapphire substrate, a magnesium oxide substrate, a gallium oxide substrate, a gallium nitride substrate, an NSTO substrate, a quartz glass substrate, an r-plane sapphire substrate, and an a-plane sapphire substrate.

[0061] In some embodiments, the shape of the second electrode 4 is rectangular or circular. The side length of the rectangle is 10 nm-10 mm, and the diameter of the circle is 10 nm-10 mm.

[0062] In some embodiments, the thickness of the first electrode 2 is 10-900 nm.

[0063] In some embodiments, the thickness of the resistive switching layer 3 is 1 to 800 nm.

[0064] In some embodiments, the thickness of the first electrode 4 is 10 to 900 nm.

[0065] In some embodiments, the substrate 1 is a Si / SiO2 / Ti substrate, that is, the substrate 1 includes a Si layer, a SiO2 layer, and a Ti layer stacked in sequence, and the first electrode 2 is located on the surface of the Ti layer, wherein the thickness of Si is 500 to 600 μm, the thickness of SiO2 is 500 to 600 nm, and the thickness of Ti is 50 to 100 nm.

[0066] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned CBRAM device based on a Ti-Cu alloy electrode, including the following steps:

[0067] S1. Prepare the first electrode on the surface of the substrate;

[0068] S2. Prepare the resistive switching layer on the surface of the first electrode;

[0069] S3. Prepare the second electrodes arranged in an array on the surface of the resistive switching layer.

[0070] Specifically, the growth methods of the first electrode, the resistive switching layer, and the second electrode of the present invention can be chemical vapor deposition, physical vapor deposition, etc.; physical vapor deposition such as magnetron sputtering.

[0071] In some embodiments, the first electrode is prepared by magnetron sputtering, wherein the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 to 0.8 Pa, the sputtering power is 1 to 40 W, and the sputtering time is 180 to 6000 s.

[0072] In some embodiments, the resistive switching layer is prepared on the surface of the first electrode by magnetron sputtering, wherein the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 to 0.8 Pa, the sputtering power is 1 to 60 W, and the sputtering time is 100 to 7000 s.

[0073] In some embodiments, the preparation method of the Ti-Cu alloy includes: using a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by magnetron sputtering; wherein, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 to 0.8 Pa, the sputtering power of Cu is 1 to 40 W, the sputtering time of Cu is 180 to 6000 s, the sputtering power of Ti is 1 to 40 W, and the sputtering time of Ti is 180 to 6000 s.

[0074] In some embodiments, the second electrode material is an active electrode material, and the active electrode material is a Ti-Cu alloy. The preparation method of the Ti-Cu alloy includes: using a Cu target and a Ti target as raw materials, and using a mask plate and a magnetron sputtering method to prepare a second electrode arranged in an array on the surface of the resistive switching layer. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2-0.8 Pa, the sputtering power of Cu is 1-40 W, the sputtering time of Cu is 180-6000 s, the sputtering power of Ti is 1-40 W, and the sputtering time of Ti is 180-6000 s.

[0075] In some embodiments, before preparing the first electrode on the surface of the substrate, the substrate is also cleaned; specifically, the cleaning method is: first, place the substrate wafer in a beaker, pour in acetone for cleaning. Since acetone is a volatile solution, it needs to be sealed with plastic wrap and then ultrasonically cleaned for 30-35 min. This step is mainly to remove impurities such as organic substances; after cleaning, take out the substrate with tweezers and then place it in another beaker, pour in anhydrous ethanol, and ultrasonically clean for 30-35 min. This step mainly removes acetone and other surface contaminants; finally, place the substrate in a beaker filled with deionized water and ultrasonically clean for 30-35 min. After the ultrasonic cleaning is completed, dry it for standby.

[0076] In some embodiments, a resistive switching layer is prepared on the surface of the first electrode by a magnetron sputtering method, which specifically includes: first, install a target material (such as a hafnium oxide target) on the DC sputtering target holder of the magnetron sputtering equipment, and turn on the molecular pump and the mechanical pump to pump air so that the air pressure in the sputtering vacuum chamber is lower than 2×10 -4 Pa; turn on the switches of argon and secondary circulating cooling water. Then stick an insulating tape on one side edge of the substrate with the first electrode prepared, fix it on the sample tray in the magnetron sputtering equipment, put it into the small chamber, and wait until the air pressure in the small chamber reaches 5×10 -3 Pa, and transfer the substrate with the first electrode prepared to the vacuum sputtering chamber; at room temperature of 25°C, use argon as an inert gas and introduce it into the vacuum chamber of the magnetron sputtering equipment. The flow rate of argon is controlled at 40-60 sccm. Turn on the AC sputtering power supply, and control the system pressure in the vacuum chamber at 0.2-0.4 Pa at room temperature. The sputtering power of the target material is 1-60 W, and the sputtering time is 100-7000 s. After the deposition is completed, turn off the AC sputtering power supply to obtain the resistive switching layer.

[0077] In some embodiments, the second electrode material is an active electrode material, and the active electrode material is a Ti-Cu alloy. The preparation method of the Ti-Cu alloy includes: using a Cu target and a Ti target as raw materials, adopting a mask plate and using co-sputtering method to prepare an array of second electrodes on the surface of the resistive switching layer. By controlling the sputtering temperature, sputtering pressure, sputtering power, and sputtering time, a high-performance CBRAM device can be prepared. The specific operation is as follows: cover one side of the resistive switching layer with a mask plate and fix it with insulating glue. The pore shapes of the mask plate are square and circular. The side length of the square is 10 nm to 10 mm, and the diameter of the circle is 10 nm to 10 mm. Therefore, the size and shape of the prepared Ti-Cu electrode are the same as those of the mask plate; install the Ti target and the Cu target on the magnetron sputtering equipment, introduce argon as an inert gas into the vacuum chamber of the magnetron sputtering equipment at room temperature of 25°C, control the flow rate of argon at 50 to 60 sccm, the pressure of the sputtering chamber is 0.2 to 0.8 Pa, turn on the radio frequency power switch, the sputtering power of Cu is 1 to 40 W, the sputtering time of Cu is 180 to 6000 s, the sputtering power of Ti is 1 to 40 W, the sputtering time of Ti is 180 to 6000 s. After deposition, turn off the DC sputtering power supply to obtain the second electrode.

[0078] The following further illustrates the CBRAM device based on the Ti-Cu alloy electrode and its preparation method of the present application with specific embodiments. This part further illustrates the content of the present invention in combination with specific embodiments, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0079] Example 1

[0080] The embodiment of the present application provides a CBRAM device based on a Ti-Cu alloy electrode, including:

[0081] A substrate;

[0082] A first electrode located on the surface of the substrate;

[0083] A resistive switching layer located on the surface of the first electrode away from the substrate;

[0084] A second electrode arranged in an array on the surface of the resistive switching layer away from the substrate;

[0085] Wherein, the material of the first electrode is an inert electrode material Pt;

[0086] The material of the second electrode is an active electrode material, and the active electrode material is a Ti-Cu alloy. The mass fraction of Ti in the Ti-Cu alloy is 25%, and the rest is Cu (i.e., the mass fraction of Cu is 75%);

[0087] The material of the resistive switching layer is hafnium oxide;

[0088] The substrate is a Si / SiO2 / Ti substrate, which includes a Si layer, a SiO2 layer, and a Ti layer stacked in sequence. The first electrode is located on the surface of the Ti layer. The thickness of the Si layer is 500 μm, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm;

[0089] The thickness of the first electrode is 200 nm;

[0090] The thickness of the resistive switching layer is 100 nm;

[0091] The thickness of the second electrode is 250 nm;

[0092] The shape of the second electrode is square, and the side length of the square is 500 μm.

[0093] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in the above Embodiment 1 includes the following steps:

[0094] S1. Ultrasonically clean the Si / SiO2 / Ti substrate with acetone for 30 min, with absolute ethanol for 20 min, and with deionized water for 10 min in sequence. After the ultrasonic cleaning is completed, dry it and set it aside for use;

[0095] S2. Deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by magnetron sputtering to obtain the first electrode. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0096] S3. Using a hafnium oxide target as the raw material, prepare a resistive switching layer on the surface of the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 40 sccm, the pressure in the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0097] S4. Using a Cu target and a Ti target as the raw materials, prepare an array of second electrodes on the surface of the resistive switching layer by using a mask and magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 10 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 3 W, and the sputtering time of Ti is 1800 s.

[0098] Embodiment 2

[0099] An embodiment of the present application provides a CBRAM device based on a Ti-Cu alloy electrode, including:

[0100] A substrate;

[0101] A first electrode located on the surface of the substrate;

[0102] A resistive switching layer located on the surface of the first electrode away from the substrate;

[0103] A second electrode, which is arranged in an array on the surface of the resistive switching layer away from the substrate;

[0104] Among them, the material of the first electrode is an inert electrode material Pt;

[0105] The material of the second electrode is an active electrode material, and the active electrode material is a Ti-Cu alloy. The mass fraction of Ti in the Ti-Cu alloy is 1%, and the remaining is Cu (that is, the mass fraction of Cu is 99%);

[0106] The material of the resistive switching layer is hafnium oxide;

[0107] The substrate includes a Si / SiO2 / Ti substrate, and the substrate includes a Si layer, a SiO2 layer, and a Ti layer stacked in sequence. The first electrode is located on the surface of the Ti layer. The thickness of the Si layer is 500 μm, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm;

[0108] The thickness of the first electrode is 200 nm;

[0109] The thickness of the resistive switching layer is 100 nm;

[0110] The thickness of the second electrode is 250 nm;

[0111] The shape of the second electrode is square, and the side length of the square is 500 μm.

[0112] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in the above embodiment 2 includes the following steps:

[0113] S1. The Si / SiO2 / Ti substrate is ultrasonically cleaned with acetone for 30 min, ultrasonically cleaned with absolute ethanol for 20 min, and ultrasonically cleaned with deionized water for 10 min in sequence. After the ultrasonic cleaning is completed, it is dried for standby;

[0114] S2. A Pt layer is deposited on the cleaned Si / SiO2 / Ti substrate by magnetron sputtering to obtain the first electrode. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0115] S3. Using hafnium oxide target as raw material, a resistive switching layer is prepared on the surface of the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 40 sccm, the pressure in the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s.

[0116] S4. Using Cu target and Ti target as raw materials, an array of second electrodes is prepared on the surface of the resistive switching layer by using a mask and magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 40 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 1 W, and the sputtering time of Ti is 1800 s.

[0117] Example 3

[0118] The embodiment of the present application provides a CBRAM device based on a Ti-Cu alloy electrode, including:

[0119] A substrate;

[0120] A first electrode, which is located on the surface of the substrate;

[0121] A resistive switching layer, which is located on the surface of the first electrode away from the substrate;

[0122] A second electrode, which is arranged in an array on the surface of the resistive switching layer away from the substrate;

[0123] Among them, the material of the first electrode is an inert electrode material Pt;

[0124] The material of the second electrode is an active electrode material, and the active electrode material is a Ti-Cu alloy. The mass fraction of Ti in the Ti-Cu alloy is 78%, and the remaining is Cu (that is, the mass fraction of Cu is 22%);

[0125] The material of the resistive switching layer is hafnium oxide;

[0126] The substrate includes a Si / SiO2 / Ti substrate, and the substrate includes a Si layer, a SiO2 layer, and a Ti layer stacked in sequence. And the first electrode is located on the surface of the Ti layer. Among them, the thickness of the Si layer is 500 μm, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm;

[0127] The thickness of the first electrode is 200 nm;

[0128] The thickness of the resistive switching layer is 100 nm;

[0129] The thickness of the second electrode is 250 nm;

[0130] The shape of the second electrode is square, and the side length of the square is 500 μm.

[0131] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in the above Embodiment 3 includes the following steps:

[0132] S1. Ultrasonically clean the Si / SiO2 / Ti substrate successively with acetone for 30 min, anhydrous ethanol for 20 min, and deionized water for 10 min. After the ultrasonic cleaning is completed, dry it for standby;

[0133] S2. Deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by magnetron sputtering to obtain the first electrode. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0134] S3. Use hafnium oxide target as the raw material, and prepare a resistive switching layer on the surface of the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 40 sccm, the pressure in the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0135] S4. Use a Cu target and a Ti target as raw materials, and prepare an array of second electrodes on the surface of the resistive switching layer by using a mask plate and magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 1 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 40 W, and the sputtering time of Ti is 1800 s.

[0136] Comparative Example 1

[0137] This Comparative Example 1 provides a preparation method of a CBRAM device based on a Cu electrode. The same as Example 1, the difference is that in step S4, the sputtering power of Ti is 0 W and the sputtering power of Cu is 10 W. It specifically includes the following steps:

[0138] S1. Ultrasonically clean the Si / SiO2 / Ti substrate successively with acetone for 30 min, anhydrous ethanol for 20 min, and deionized water for 10 min. After the ultrasonic cleaning is completed, dry it for standby;

[0139] S2. Deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by magnetron sputtering to obtain the first electrode. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0140] S3. Use hafnium oxide target as the raw material and prepare a resistive switching layer on the surface of the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 40 sccm, the pressure in the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0141] S4. Use Cu target and Ti target as the raw materials, and use a mask plate and magnetron sputtering method to prepare an array of second electrodes on the surface of the resistive switching layer. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 10 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 0 W, and the sputtering time of Ti is 1800 s.

[0142] Comparative Example 2

[0143] This Comparative Example 2 provides a preparation method of an OxRAM device based on a Ti electrode. Similar to Example 1, the difference is that in step S4, the sputtering power of Ti is 10 W and the sputtering power of Cu is 0 W. The specific steps are as follows:

[0144] S1. Ultrasonically clean the Si / SiO2 / Ti substrate with acetone for 30 min, ultrasonically clean it with absolute ethanol for 20 min, and ultrasonically clean it with deionized water for 10 min. After the ultrasonic cleaning is completed, dry it for later use;

[0145] S2. Deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by magnetron sputtering to obtain the first electrode. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0146] S3. Use hafnium oxide target as the raw material and prepare a resistive switching layer on the surface of the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the temperature is room temperature 25°C, the flow rate of argon is 40 sccm, the pressure in the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0147] S4. Using a Cu target and a Ti target as raw materials, a second electrode arranged in an array is prepared on the surface of the resistive switching layer by using a mask and magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are as follows: the temperature is room temperature of 25 °C, the flow rate of argon is 50 sccm, the pressure in the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 0 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 10 W, and the sputtering time of Ti is 1800 s.

[0148] Performance Test

[0149] The prepared CBRAM devices / OxRAM devices in Example 1 and Comparative Examples 1-2 are respectively subjected to corresponding performance tests, and all the tests are carried out on an Agilent B1500A semiconductor parameter analyzer test platform.

[0150] Specifically, during the test, the CBRAM devices in Example 1 and Comparative Example 1 are respectively placed on the probe table, and two probes are used to contact the first electrode and the second electrode of the device respectively. A DC scanning voltage of -0.7 V to 1.5 V is applied to the second electrode, and the first electrode is grounded to obtain the I-V curve.

[0151] Figure 2 It is the I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 1.

[0152] Figure 8 It is the I-V curve diagram of the CBRAM device based on the Cu alloy electrode prepared in Comparative Example 1.

[0153] From Figure 2 and Figure 8 it can be seen that the I-V curve shows obvious bipolar resistive switching characteristics, and one scanning voltage cycle includes four parts: first, scan from 0 V to -0.7 V, then from -0.7 V to 0 V, then from 0 V to 1.5 V, and finally from 1.5 V to 0 V, that is, one scanning cycle is completed. The number of scanning steps in each part is 101. To prevent the device from being broken down due to excessive current during the test, a limiting current of 5 mA needs to be set when applying a positive voltage. When the voltage scans from 0 V to -0.7 V, it can be seen that the current flowing through the device gradually increases. When the voltage reaches about -0.6 V, the current of the device suddenly decreases, and at this time the device changes from the low resistance state to the high resistance state, and this process is called the reset process; when the voltage scans from 0 V to 1.5 V, the current flowing through the device first increases. When the voltage reaches a certain value, the current flowing through the device suddenly increases, and at this time the device changes back from the high resistance state to the low resistance state, and this process is the set process. By comparison Figure 2 and Figure 8It can be seen that the device of Example 1 has better stability. This is because the use of a Ti-Cu alloy electrode to replace the Cu electrode limits the number of Cu atoms that form conductive filaments injected from the electrode, which can greatly improve the durability of the CBRAM device.

[0154] The resistance values of the high-resistance state (HRS) and low-resistance state (LRS) of the CBRAM devices in Example 1 and Comparative Example 1 were read at a voltage of -0.098V, and the resistance distribution diagrams of the two devices were obtained, as Figure 3 and 9 shown.

[0155] Figure 3 is the resistance state distribution diagram of the CBRAM device based on the Ti-Cu electrode in Example 1.

[0156] Figure 9 is the resistance state distribution diagram of the CBRAM device based on the Cu alloy electrode in Comparative Example 1.

[0157] From Figure 3 and Figure 9 it can be seen that the R HRS / R LRS of both devices is about 10. However, in Comparative Example 1, the device began to show a device failure state at about the 20th cycle, while the device in Example 1 could maintain stable resistance state switching for 300 cycles without failure, and the device durability was greatly improved.

[0158] Figure 10 is the I-V curve diagram of the OxRAM device based on the Ti electrode in Comparative Example 2.

[0159] The resistance values of the high-resistance state and low-resistance state of the OxRAM device based on the Ti electrode in Comparative Example 2 were read at a voltage of -0.098V, and the resistance distribution diagram of the device was obtained, as Figure 11 shown.

[0160] From Figure 11 it can be seen that the R HRS / R LRSBoth are approximately 10. However, for the device in Comparative Example 2, device failure had already started to occur at around the 35th cycle, while the device in Example 1 could maintain stable resistance state switching for 300 cycles without failure, greatly improving the device durability. The CBRAM device with a Ti-Cu electrode has a conductive filament composed of Cu, while the OxRAM device with a Ti electrode (i.e., Oxide Random Access Memory) has a conductive filament composed of oxygen vacancies. Due to the relatively active property of Ti, under the action of an electric field, the migration of oxygen ions causes TiO x to gradually form at the x interface, and more oxygen vacancies are formed in HfO x , resulting in the device requiring a stronger electric field to cause the fracture of the conductive filament. Therefore, the Ti-Cu alloy electrode device has better stability than the Ti electrode device.

[0161] Figure 4 Figure 10 is the I-V curve diagram of the CBRAM device with a Ti-Cu electrode prepared in Example 2;

[0162] Figure 5 Figure 14 is the resistance state distribution diagram of the CBRAM device with a Ti-Cu alloy electrode prepared in Example 2;

[0163] Figure 6 Figure 18 is the I-V curve diagram of the CBRAM device with a Ti-Cu electrode prepared in Example 3;

[0164] Figure 7 Figure 22 is the resistance state distribution diagram of the CBRAM device with a Ti-Cu electrode prepared in Example 3.

[0165] From Figures 4 - 7 , it can be seen that compared with the conductive bridge random access memory with a pure metal electrode (Comparative Example 1 and Comparative Example 2), the CBRAM devices prepared in Example 2 and Example 3 have better stability and consistency. Figure 5 and Figure 7 are the resistance state distribution diagrams of the devices in Example 2 and Example 3 respectively. It can be seen that compared with Comparative Example 1 and Comparative Example 2, the Cu-Ti alloy electrode has a certain improvement in the durability of the device. Among them, the durability of the CBRAM device prepared in Example 2 is about 40 cycles, the durability of the CBRAM device prepared in Example 3 is about 78 cycles, the durability of the device prepared in Comparative Example 1 is only 20 cycles, and the durability of the device prepared in Comparative Example 2 is only 35 cycles.

[0166] Figure 12 Figure 35 is the XPS analysis diagram of the Cu element in the Ti-Cu alloy electrode prepared in Example 2.

[0167] Figure 13 It is the XPS analysis diagram of Ti element in the Ti-Cu alloy electrode prepared in Example 2.

[0168] Figure 14 It is the XPS analysis diagram of Cu element in the Ti-Cu alloy electrode prepared in Example 3.

[0169] Figure 15 It is the XPS analysis diagram of Ti element in the Ti-Cu alloy electrode prepared in Example 3.

[0170] Figures 12 - 15 In it, Experimental represents the original data image of XPS analysis, Calculated represents the fitting data after the original data is calculated and iterated, which is for more convenient analysis of the element valence state and composition, and Background represents the baseline, whose main function is to provide a reliable benchmark for quantitative analysis.

[0171] From Figure 12 and Figure 13 it can be calculated that the content of Cu in Example 2 is 99%. From Figure 14 and Figure 15 it can be calculated that the content of Cu in Example 3 is 22%. From Figure 12 and Figure 14 it can be seen that there are multiple states of Cu in the alloy electrode, including metallic Cu, Cu + and Cu 2+ , corresponding to metallic Cu, CuO2 and CuO. From Figure 13 and Figure 15 it can be seen that Ti also exists in three states: metallic Ti, Ti 3+ and Ti 4+ . In the Cu-Ti alloy, with the increase of Ti content, the content of Cu 2+ increases, that is, more CuO is introduced into the electrode. CuO is more difficult to release Cu atoms in the redox reaction, so the injection of Cu atoms from the electrode to the intermediate layer can be restricted, thereby improving the durability of the device. The conductive filaments are formed by Cu atoms generated from Cu and CuO2.

[0172] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A CBRAM device based on a Ti-Cu alloy electrode, characterized in that, Comprising: A substrate; A first electrode located on the surface of the substrate; A resistive switching layer located on the surface of the first electrode away from the substrate; A second electrode, which is arranged in an array on the surface of the resistive switching layer away from the substrate; Wherein, the materials of the first electrode and the second electrode are active electrode materials or inert electrode materials. When the material of the first electrode is an active electrode material, the material of the second electrode is an inert electrode material; when the material of the first electrode is an inert electrode material, the material of the second electrode is an active electrode material; The active electrode material is a Ti-Cu alloy; The material of the resistive switching layer includes any one of hafnium oxide, silicon oxide, zirconium oxide, germanium telluride, and germanium selenide.

2. The CBRAM device based on the Ti-Cu alloy electrode according to claim 1, characterized in that, The mass fraction of Cu in the Ti-Cu alloy is 22% - 99%, and the remainder is Ti.

3. The CBRAM device based on the Ti-Cu alloy electrode according to claim 1, characterized in that, The inert electrode material includes at least one of Ti, Pt, W, and TiN.

4. The CBRAM device based on the Ti-Cu alloy electrode according to claim 1, wherein, The substrate includes any one of Si / SiO2 / Ti substrate, Si substrate, SiO2 substrate, c-plane sapphire substrate, magnesium oxide substrate, gallium oxide substrate, gallium nitride substrate, NSTO substrate, quartz glass substrate, r-plane sapphire substrate, and a-plane sapphire substrate.

5. The CBRAM device based on the Ti-Cu alloy electrode according to claim 1, wherein The shape of the second electrode is rectangular or circular. The side length of the rectangle is 10 nm - 10 mm, and the diameter of the circle is 10 nm - 10 mm.

6. The CBRAM device based on the Ti-Cu alloy electrode according to claim 1, characterized in that, The thickness of the first electrode is 10 - 900 nm; The thickness of the resistive switching layer is 1 - 800 nm; The thickness of the second electrode is 10 - 900 nm.

7. A method for preparing a CBRAM device based on a Ti-Cu alloy electrode according to any one of claims 1 to 6, characterized in that, Including the following steps: Preparing a first electrode on the surface of the substrate; Preparing a resistive switching layer on the surface of the first electrode; Preparing a second electrode arranged in an array on the surface of the resistive switching layer.

8. The manufacturing method of the CBRAM device based on the Ti-Cu alloy electrode as claimed in claim 7, wherein, The preparation method of the Ti-Cu alloy includes: using a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 - 0.8 Pa, the sputtering power of Cu is 1 - 40 W, the sputtering time of Cu is 180 - 6000 s, the sputtering power of Ti is 1 - 40 W, and the sputtering time of Ti is 180 - 6000 s.

9. The manufacturing method of the CBRAM device based on the Ti-Cu alloy electrode according to claim 7, characterized in that, Preparing the first electrode by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 - 0.8 Pa, the sputtering power is 1 - 40 W, and the sputtering time is 180 - 6000 s.

10. The preparation method of the CBRAM device based on the Ti-Cu alloy electrode according to claim 7, characterized in that, Preparing the resistive switching layer by magnetron sputtering. Among them, the process parameters controlled during magnetron sputtering are: the pressure in the sputtering chamber is 0.2 - 0.8 Pa, the sputtering power is 1 - 60 W, and the sputtering time is 100 - 7000 s.

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