Ferroelectric memory cell, manufacturing method thereof, ferroelectric memory and electronic equipment

Abstract

The invention provides a ferroelectric storage unit and a manufacturing method thereof, a ferroelectric memory and electronic equipment, the ferroelectric storage unit comprises a first electrode, a composite electrode and a ferroelectric storage layer arranged between the first electrode and the composite electrode, the composite electrode comprises a conductive buffer layer, a conductive oxygen absorption layer and a second electrode, the Gibs of the oxide corresponding to the conductive oxygen absorption layer is smaller than the Gibs of the oxide corresponding to the first electrode, so that the conductive oxygen absorption layer can absorb oxygen in an oxide layer formed between the first electrode and the ferroelectric storage layer, the amount of oxygen in the oxide layer is reduced, the thickness of the oxide layer is reduced, continuous formation of the oxide layer is inhibited, the loss of retention characteristics is reduced, and the performance of the ferroelectric storage device is improved. Therefore, the performance of the ferroelectric storage unit is improved. Moreover, the conductive buffer layer can prevent the conductive oxygen absorption layer from being in direct contact with the ferroelectric storage layer, so that the situation that adsorption of oxygen in the oxide layer cannot be achieved or weakened is avoided.

Description

Technical Field

[0001] The present application relates to the field of storage technology, and in particular to a ferroelectric storage unit, a manufacturing method thereof, a ferroelectric storage device and an electronic device. Background Art

[0002] Ferroelectric memory has the advantages of low read and write voltage, low power consumption, small device size, high read and write speed, good cycle performance, good radiation resistance and non-volatility, and is expected to be used to build a new generation of non-volatile memory. Compared with traditional ferroelectric materials, hafnium-based ferroelectric materials not only have superior miniaturization characteristics, but also can overcome the technical difficulties and bottlenecks such as incompatibility between traditional ferroelectric materials and complementary metal oxide semiconductor (CMOS) processes, difficulty in miniaturization, and difficulty in achieving high-density integration. Therefore, hafnium-based ferroelectric devices are expected to become the core unit of future new ferroelectric memories.

[0003] However, there are still some problems with ferroelectric memory, such as loss of retention characteristics and imprinting effect. The retention characteristic refers to the ability to maintain a certain polarization state. If the retention characteristic is lost, the polarization strength will decrease over time. This means that the stored data in the ferroelectric memory cell will become blurred over time, making it difficult to read the stored data accurately. The imprinting effect refers to the ferroelectric polarization biased in a certain direction, which appears as a left or right shift of the hysteresis loop on the polarization loop. In the ferroelectric memory cell, it will make one storage state (assuming that the data "1" is stored) more obvious, while the other storage state (corresponding to the storage data "0") is difficult to identify, causing misreading. Therefore, for ferroelectric memory, reducing the loss of retention characteristics and weakening the imprinting effect have become urgent problems to be solved. Summary of the invention

[0004] The present application provides a ferroelectric memory cell, a manufacturing method thereof, a ferroelectric memory and an electronic device, which are used to reduce the loss of retention characteristics in the ferroelectric memory, weaken the imprinting effect, and improve the performance of the ferroelectric memory.

[0005] In a first aspect, an embodiment of the present application provides a ferroelectric memory cell, which may include: a first electrode, a composite electrode, and a ferroelectric memory layer arranged between the first electrode and the composite electrode, the composite electrode including: a conductive buffer layer, a conductive oxygen absorption layer, and a second electrode, which are arranged in sequence along a direction from the first electrode to the ferroelectric memory layer; wherein the Gibbs free energy (abbreviated as Gibs) of the oxide corresponding to the conductive oxygen absorption layer is less than the Gibs of the oxide corresponding to the first electrode, so that the adsorption capacity of the conductive oxygen absorption layer for oxygen is higher than the adsorption capacity of the first electrode for oxygen, so that the conductive oxygen absorption layer can absorb oxygen in the oxide layer formed between the first electrode and the ferroelectric memory layer, and the oxygen vacancies in the ferroelectric memory layer can serve as an oxygen transmission channel to transmit oxygen from the oxide layer between the first electrode and the ferroelectric memory layer to the conductive oxygen absorption layer, so that the amount of oxygen in the oxide layer between the first electrode and the ferroelectric memory layer can be reduced, thereby reducing the thickness of the oxide layer and inhibiting the continued formation of the oxide layer. Since the oxide layer has the function of weakening the retention characteristics and the imprinting effect, thinning the oxide layer can avoid weakening the retention characteristics, thereby reducing the loss of the retention characteristics, and can also weaken the imprinting effect, thereby improving the performance of the ferroelectric memory cell. In addition, the provision of the conductive buffer layer can prevent the conductive oxygen absorbing layer from directly contacting the ferroelectric memory layer, thereby preventing the conductive oxygen absorbing layer from absorbing oxygen in the ferroelectric memory layer when in direct contact and failing to or weakening the adsorption of oxygen in the oxide layer.

[0006] Furthermore, since the conductive oxygen absorbing layer can absorb oxygen in the oxide layer between the first electrode and the ferroelectric storage layer, and the oxygen vacancies in the ferroelectric storage layer serve as oxygen transmission channels, the oxygen vacancies in the ferroelectric storage layer tend to migrate to the oxide, thereby adjusting the distribution gradient of the oxygen vacancies in the ferroelectric storage layer, so that the density of the oxygen vacancies in the ferroelectric storage layer gradually increases along the direction from the composite electrode to the first electrode, which can also inhibit the continued formation of the oxide layer between the first electrode and the ferroelectric storage layer; of course, the first electrode can play a certain role in chemical decomposition of the oxide layer, which can also inhibit the continued formation of the oxide layer, thereby further improving the performance of the ferroelectric storage unit. It should be understood that the thermodynamic stability of the oxide in the ferroelectric storage layer is higher than the stability of the oxide corresponding to the first electrode, and the conductive oxygen absorbing layer is more inclined to absorb oxygen in the oxide with poor stability, while the oxygen in the oxide with good stability will not be absorbed or the amount of adsorption is so small that it can be ignored.

[0007] Exemplarily, the first electrode can be made of conductive metal, metal oxide, metal nitride and other materials, and the first electrode can include one or more metal elements. When the first electrode includes multiple metals, the Gibs of the oxide corresponding to the conductive oxygen absorption layer is smaller than the Gibs of the oxide corresponding to each metal included in the first electrode, so that the conductive oxygen absorption layer can absorb oxygen in the oxide corresponding to each metal in the first electrode, thereby reducing the thickness of the oxide between the first electrode and the ferroelectric storage layer, further improving the retention characteristics and weakening the imprinting effect, and improving the performance of the ferroelectric storage unit.

[0008] For the conductive buffer layer: its manufacturing material may include at least one of TiN and TaN. Of course, other materials that can realize the function of the conductive buffer layer are also applicable in the embodiment of the present application. In addition, the thickness of the conductive buffer layer can be set to 1nm to 20nm. Setting the thickness of the conductive buffer layer in a suitable range can, on the one hand, avoid direct contact between the conductive oxygen absorbing layer and the ferroelectric storage layer, and on the other hand, avoid the overall thickness of the ferroelectric storage unit being too large, thereby avoiding increasing the volume of the ferroelectric storage unit.

[0009] For the conductive oxygen absorbing layer: its manufacturing material may include at least one of yttrium, titanium, lanthanum, scandium, copper, aluminum, tantalum, and hafnium. Of course, other materials that can realize the conductive oxygen absorbing layer are also applicable in the embodiments of the present application. In addition, the thickness of the conductive oxygen absorbing layer can be set to 0.5nm to 5nm. The conductive oxygen absorbing layer is set to a suitable thickness. On the one hand, it can absorb oxygen in the oxide layer formed between the first electrode and the ferroelectric storage layer to reduce the thickness of the oxide layer. On the other hand, it can avoid the overall thickness of the ferroelectric storage unit being too large, thereby avoiding increasing the volume of the ferroelectric storage unit.

[0010] For the second electrode: the manufacturing material of the second electrode includes a conductive material, and the conductive material does not contain oxygen, so that the conductive oxygen absorption layer can fully absorb the oxygen in the oxide layer between the first electrode and the ferroelectric storage layer, and maximize the effect of thinning the thickness of the oxide layer, thereby further improving the retention characteristics of the ferroelectric storage layer, weakening the imprinting effect, and further improving the performance of the ferroelectric storage unit. In addition, under the action of external force, stress can be applied to the ferroelectric storage layer through the first electrode and the second electrode to promote the crystallization of the material in the ferroelectric storage layer, which is conducive to the formation of the ferroelectric phase in the ferroelectric storage layer, thereby facilitating the formation of the ferroelectric storage unit, so that the thickness of the first electrode can be set to 1nm to 100nm, and the thickness of the second electrode can be set to 30nm to 100nm, so that the first electrode and the second electrode can withstand the action of external force.

[0011] The composite electrode may also include: a conductive adhesion layer disposed between the conductive oxygen absorbing layer and the second electrode, the conductive adhesion layer can increase the adhesion strength between the conductive oxygen absorbing layer and the second electrode, and avoid the conductive oxygen absorbing layer and the second electrode from falling off, thereby improving the reliability of the ferroelectric memory cell. Among them, the conductive adhesion layer can be made of at least one of TiN and TaN. Of course, other materials that can realize the function of the conductive adhesion layer are also applicable in the embodiment of the present application. In addition, the thickness of the conductive adhesion layer can be set to 1nm to 20nm. Setting the thickness of the conductive adhesion layer within a suitable range can, on the one hand, increase the adhesion strength between the conductive oxygen absorbing layer and the second electrode, and on the other hand, avoid the overall thickness of the ferroelectric memory cell being too large, thereby avoiding increasing the volume of the ferroelectric memory cell.

[0012] For the ferroelectric storage layer, the material thereof may be a doped hafnium oxide material. For example, the material of the ferroelectric storage layer may include: zirconium-doped hafnium oxide (such as Hf 0.5 Zr 0.5 O2), zirconium and lanthanum doped hafnium oxide (such as La doped Hf 0.5 Zr 0.5 O2), zirconium and yttrium-doped hafnium oxide (such as Y-doped Hf 0.5 Zr 0.5 O2), zirconium and strontium doped hafnium oxide (such as Sr doped Hf 0.5 Zr 0.5 O2), zirconium and gadolinium-doped hafnium oxide (such as Gd-doped Hf 0.5 Zr 0.5 O2), zirconium, gadolinium, and lanthanum-doped hafnium oxide (such as Gd / La co-doped Hf 0.5 Zr 0.5 O2), silicon-doped hafnium oxide (such as Si-doped HfO2), aluminum-doped hafnium oxide, lanthanum-doped hafnium oxide, yttrium-doped hafnium oxide, gadolinium-doped hafnium oxide, strontium-doped hafnium oxide, etc. In addition, the thickness of the ferroelectric storage layer can be set to 1nm to 100nm. Setting the thickness of the ferroelectric storage layer within a suitable range can, on the one hand, be beneficial to the formation of the ferroelectric phase and avoid the ferroelectric phase being difficult to form due to the ferroelectric storage layer being too thick. On the other hand, it can avoid the overall thickness of the ferroelectric storage unit being too large, thereby avoiding an increase in the volume of the ferroelectric storage unit.

[0013] Exemplarily, the ferroelectric memory cell may include: a transistor and a storage capacitor. The storage scheme provided in the embodiment of the present application may be applied in the storage capacitor, that is, the first electrode, the ferroelectric storage layer and the composite electrode may form a storage capacitor. Moreover, when the ferroelectric memory cell is arranged on the substrate, the first electrode, the ferroelectric storage layer and the composite electrode may be stacked in a direction perpendicular to the substrate surface, and the ferroelectric storage layer is arranged between the first electrode and the composite electrode, and the storage capacitor may be regarded as a storage capacitor with a two-dimensional structure. Alternatively, the first electrode and the insulating layer may be alternately stacked in a direction perpendicular to the substrate surface to form a stacked structure, and then a through hole is dug out in the stacked structure, the through hole runs through the stacked structure along the stacking direction, and then the ferroelectric storage layer and the composite electrode are sequentially filled in the through hole, the ferroelectric storage layer is arranged between the stacked structure and the composite electrode, and the stacking direction of the conductive buffer layer, the conductive oxygen absorption layer and the second electrode in the composite electrode is perpendicular to the extension direction of the through hole, and the storage capacitor formed at this time may be regarded as a storage capacitor with a three-dimensional structure.

[0014] In the second aspect, the embodiment of the present application also provides a method for manufacturing a ferroelectric memory cell. The ferroelectric memory cell manufactured by the manufacturing method can be the ferroelectric memory cell described in the first aspect and any possible implementation of the first aspect. The manufacturing method may include: forming a first electrode; forming a ferroelectric memory layer on the first electrode; forming a conductive buffer layer on the ferroelectric memory layer; forming a conductive oxygen absorption layer on the conductive buffer layer, wherein the Gibbs free energy of the oxide corresponding to the conductive oxygen absorption layer is less than the Gibbs free energy of the oxide corresponding to the first electrode; forming a second electrode on the conductive oxygen absorption layer, so that the conductive buffer layer, the conductive oxygen absorption layer and the second electrode form a composite electrode. In this way, the conductive oxygen absorption layer can absorb oxygen in the oxide layer between the first electrode and the ferroelectric memory layer, and the oxygen vacancies in the ferroelectric memory layer can serve as a transmission channel for oxygen, and oxygen is transmitted from the oxide layer between the first electrode and the ferroelectric memory layer to the conductive oxygen absorption layer, so that the amount of oxygen in the oxide layer between the first electrode and the ferroelectric memory layer can be reduced, thereby reducing the thickness of the oxide layer and inhibiting the continued formation of the oxide layer. Since the oxide layer has the function of weakening the retention characteristics and the imprinting effect, thinning the oxide layer can avoid weakening the retention characteristics, thereby reducing the loss of the retention characteristics, and can also weaken the imprinting effect, thereby improving the performance of the ferroelectric memory cell. In addition, the provision of the conductive buffer layer can prevent the conductive oxygen absorbing layer from directly contacting the ferroelectric memory layer, thereby preventing the conductive oxygen absorbing layer from absorbing oxygen in the ferroelectric memory layer when in direct contact and failing to or weakening the adsorption of oxygen in the oxide layer.

[0015] Exemplarily, when the ferroelectric memory cell further includes a conductive adhesion layer disposed between the conductive oxygen absorbing layer and the second electrode, the manufacturing method may further include: forming a conductive adhesion layer on the conductive oxygen absorbing layer after forming the conductive oxygen absorbing layer and before forming the second electrode. The conductive adhesion layer can increase the adhesion strength between the conductive oxygen absorbing layer and the second electrode, and prevent the conductive oxygen absorbing layer from falling off from the second electrode, thereby improving the reliability of the ferroelectric memory cell.

[0016] When manufacturing the first electrode, the ferroelectric storage layer and the composite electrode, physical vapor deposition or chemical vapor deposition can be used, and the manufacturing methods used for each film layer can be the same or different, and can be selected according to actual needs. In addition, in order to obtain the ferroelectric storage layer, the manufacturing method can also include: heat treatment of the formed ferroelectric storage layer, and the specific heat treatment process can include: heating the formed ferroelectric storage layer, and rapidly cooling it to a second temperature when the temperature rises to a first temperature, wherein the first temperature is greater than the second temperature, and by heating and cooling, the ferroelectric storage layer can exhibit ferroelectric properties, thereby realizing the function of the ferroelectric storage unit. Among them, the selection of the first temperature and the second temperature can be set according to the manufacturing material of the ferroelectric storage layer, and is not limited here. In addition, the heat treatment process can be performed after the ferroelectric storage layer is formed and before the composite electrode is formed, or it can be performed after the composite electrode is formed, or it can be performed after any layer in the composite electrode is formed, as long as the ferroelectric storage layer can exhibit ferroelectric properties, and the execution time of the heat treatment is not limited here.

[0017] Exemplarily, when the storage solution provided in the embodiment of the present application is applied to a storage capacitor, and the storage capacitor is a three-dimensional structure, the formation of the first electrode may specifically include: forming an alternately arranged first electrode and an insulating layer to obtain a stacked structure; forming a through hole in the stacked structure, the through hole passing through the stacked structure along the stacking direction; so that the ferroelectric storage layer and the composite electrode to be subsequently manufactured are formed in the through hole, thereby obtaining a three-dimensional storage capacitor. Among them, the manufacturing material of the insulating layer can be any material that can play an insulating role, and is not limited here.

[0018] It should be understood that since the principle of solving the problem by the ferroelectric memory unit manufactured by this manufacturing method is similar to the principle of solving the problem by the aforementioned ferroelectric memory unit, the embodiments and technical effects of this manufacturing method can refer to the embodiments and technical effects of the aforementioned ferroelectric memory unit, and the repeated parts will not be repeated.

[0019] In the third aspect, the embodiment of the present application further provides a ferroelectric memory, which may include: a storage array and a controller coupled to the storage array, the storage array including a plurality of ferroelectric memory cells as described in the first aspect and any possible implementation of the first aspect, the plurality of ferroelectric memory cells being deployed in an array manner; a storage array for storing data; a controller for writing data to the storage array or reading data from the storage array. In this way, on the basis of reducing the loss of the retention characteristics of the ferroelectric memory cell and weakening the imprinting effect, the loss of the retention characteristics of the ferroelectric memory is also reduced and the imprinting effect is also weakened, thereby improving the performance of the ferroelectric memory. Since the principle of solving the problem by the ferroelectric memory is similar to the principle of solving the problem by the aforementioned ferroelectric memory cell, the embodiments and technical effects of the ferroelectric memory can refer to the embodiments and technical effects of the aforementioned ferroelectric memory cell, and the repeated parts will not be repeated.

[0020] Exemplarily, when the ferroelectric memory cell includes a transistor and at least one storage capacitor, the ferroelectric memory may also include: a word line, a bit line, and at least one control line. When the ferroelectric memory cells in the storage array are deployed in an array manner, the ferroelectric memory cells in the same row can be connected to the same word line, and the ferroelectric memory cells in different rows are connected to different word lines, so that different word lines can control the conduction and disconnection of transistors in different rows of ferroelectric memory cells. The ferroelectric memory cells in the same column can be connected to the same bit line, and the ferroelectric memory cells in different columns are connected to different bit lines, so that different bit lines can provide voltages to different rows of ferroelectric memory cells. Each control line is respectively connected to the second end of each storage capacitor of each ferroelectric memory cell, that is, each ferroelectric memory cell is connected to each control line, and the number of control lines set is the same as the number of storage capacitors set in the ferroelectric memory cell, and is set one by one. Thus, each ferroelectric memory cell can be accurately controlled through the word line and the bit line, and the accurate writing and reading of data can be achieved under the action of the voltage provided by each control line.

[0021] In a fourth aspect, an embodiment of the present application further provides an electronic device, which may include: a circuit board, and a ferroelectric memory as described in the second aspect and any possible implementation of the second aspect, wherein the ferroelectric memory is arranged on the circuit board. In this way, on the basis of the improved performance of the ferroelectric memory, the performance of the electronic device is also improved. Since the principle of solving the problem by the electronic device is similar to the principle of solving the problem by the aforementioned ferroelectric memory, the embodiments and technical effects of the electronic device can refer to the embodiments and technical effects of the aforementioned ferroelectric memory, and the repeated parts will not be repeated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of a ferroelectric memory provided in an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of a ferroelectric memory cell provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the principles provided for the embodiments of the present application;

[0026] Figure 5 A schematic diagram of the structure of another ferroelectric memory cell provided in an embodiment of the present application;

[0027] Figure 6 A schematic diagram of the structure of another ferroelectric memory cell provided in an embodiment of the present application;

[0028] Figure 7 A schematic diagram of the structure of another ferroelectric memory cell provided in an embodiment of the present application;

[0029] Figure 8 A schematic diagram of a manufacturing process of a ferroelectric memory cell provided in an embodiment of the present application;

[0030] Fig. 9 A schematic diagram of a manufacturing process of another ferroelectric memory cell provided in an embodiment of the present application;

[0031] Fig.10 A schematic diagram of the manufacturing process of another ferroelectric memory cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0033] It should be noted that the same reference numerals in the drawings of this application represent the same or similar structures, and thus their repeated description will be omitted. The words expressing positions and directions described in this application are all explained using the drawings as examples, but they can be changed as needed, and the changes are included in the protection scope of this application. The drawings of this application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0034] In order to facilitate understanding of the technical solution provided by the embodiments of the present application, the application scenario provided by the embodiments of the present application is first explained below.

[0035] The storage solution provided in the embodiments of the present application can be widely used in devices with storage functions, for example, it can be applicable to storage devices with only storage functions, such as ferroelectric memory, and it can also be applicable to electronic devices with storage functions and other functions (such as read and write functions). The electronic device can be a portable electronic device that includes functions such as a personal digital assistant and / or a music player, such as a mobile phone, a tablet computer, a wearable device with wireless communication functions (such as a smart watch), or a car-mounted device. Exemplary embodiments of portable electronic devices include but are not limited to devices equipped with Or a portable electronic device with other operating systems. The portable electronic device may also be a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present application, the electronic device may also be a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0036] Figure 1 The schematic diagram of the structure of the ferroelectric memory when it is used in an electronic device is shown as an example. Figure 1 The electronic device includes a housing 300 and a circuit board 200 disposed in the housing 300, and a ferroelectric memory 100 is disposed on the circuit board 200. The ferroelectric memory 100 may be a non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. It should be noted that the memory described in the present application is intended to include but is not limited to these and any other suitable types of memory.

[0037] Figure 2 The internal structure diagram of a ferroelectric memory 100 applicable to the embodiment of the present application is exemplarily shown. It should be understood that the ferroelectric memory 100 shown in the figure is only an example, and the ferroelectric memory 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure can be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and / or application-specific integrated circuits.

[0038] like Figure 2As shown, the ferroelectric memory 100 may include a storage array 110 and a controller 120. The storage array 110 is used to store data, and is a matrix array composed of multiple ferroelectric storage units arranged in rows and columns. Each ferroelectric storage unit can be used to store 1 or more bits of binary data, such as "0" and / or "1". Among them, multiple ferroelectric storage units can be located in different tracks of the same disk, or in different disks, without specific limitation. The controller 120 is used to read or write data in the storage array 110, and is a device with control capabilities. The controller 120 can be connected to the storage array 110, and the connection method can be, for example, a bus connection. The controller 120 may include multiple functional components, such as but not limited to a driving circuit, a decoding circuit, and an amplifier circuit. These functional components can be set as separate devices, or they can be implemented in one device, or they can be set in at least two devices in any combination, without specific limitation.

[0039] Continue to refer to Figure 2 As shown, the controller 120 can also be connected to an external device 400, which can be, for example, a read / write device or a processor. When reading / writing data, the external device 400 can send a read / write request to the controller 120, and the read / write request carries the row address information and column address information of the target ferroelectric memory cell to be read / written. The controller 120 decodes the row address information in the read / write request to determine the row where the target ferroelectric memory cell is located, and turns on all ferroelectric memory cells corresponding to the row where the target ferroelectric memory cell is located by decoding the selection signal, and then decodes the column address information in the read / write request to obtain the column where the target ferroelectric memory cell is located, and then reads the data stored in the target ferroelectric memory cell at the column and sends it to the external device 400, or writes the data to be written sent by the external device 400 into the target ferroelectric memory cell at the column.

[0040] although Figure 2 Not shown in the figure, the ferroelectric memory 100 may also include other components, such as a main memory data register (memory data register, MDR) and a main memory address register (memory address register, MAR), etc., which are not described in detail here.

[0041] In order to reduce the loss of retention characteristics in ferroelectric memory, weaken the imprinting effect, and improve the performance of ferroelectric memory, the embodiment of the present application provides a ferroelectric memory unit, such as Figure 3The schematic diagram of the structure of the ferroelectric memory cell in the embodiment of the present application is shown as an example. The ferroelectric memory cell may include: a first electrode 10, a composite electrode 20, and a ferroelectric memory layer 30 arranged between the first electrode 10 and the composite electrode 20, wherein the composite electrode 20 includes: a first electrode 10 pointing to the ferroelectric memory layer 30 along the direction from the first electrode 10 to the ferroelectric memory layer 30 (i.e. Figure 3 In the z direction shown in FIG, a conductive buffer layer 21, a conductive oxygen absorbing layer 22 and a second electrode 23 are sequentially arranged; wherein the Gibs of the oxide corresponding to the conductive oxygen absorbing layer 22 is smaller than the Gibs of the oxide corresponding to the first electrode 10.

[0042] See also Figure 4 As shown in the schematic diagram of the principle, the Gibs of the oxide corresponding to the conductive oxygen absorbing layer 22 is smaller than the Gibs of the oxide corresponding to the first electrode 10, so that the adsorption capacity of the conductive oxygen absorbing layer 22 to oxygen is higher than the adsorption capacity of the first electrode 10 to oxygen, so that the conductive oxygen absorbing layer 22 can adsorb oxygen in the oxide layer m0 formed between the first electrode 10 and the ferroelectric storage layer 30 (such as Figure 4 ), and the oxygen vacancies in the ferroelectric memory layer 30 (as shown by the black circles in FIG. Figure 4 The circles filled with grids in the middle) can serve as a transmission channel for oxygen, and transmit oxygen from the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30 to the conductive oxygen absorbing layer 22. Figure 4 The dotted arrow in the figure indicates that the oxygen in the oxide layer m0 migrates upward through the transmission channel, which can reduce the amount of oxygen in the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30, thereby reducing the thickness of the oxide layer m0 and inhibiting the further formation of the oxide layer m0. Since the oxide layer m0 has the function of weakening the retention characteristics and the imprinting effect, thinning the oxide layer m0 can avoid weakening the retention characteristics, thereby reducing the loss of the retention characteristics, and can also weaken the imprinting effect, thereby improving the performance of the ferroelectric storage unit. In addition, the provision of the conductive buffer layer 21 can prevent the conductive oxygen absorbing layer 22 from directly contacting the ferroelectric storage layer 30, thereby preventing the conductive oxygen absorbing layer 22 from absorbing oxygen in the ferroelectric storage layer 30 when in direct contact, and failing to or weakening the adsorption of oxygen in the oxide layer m0. In addition, since the oxide formed by the conductive oxygen absorbing layer 22 after oxygen absorption has a large oxygen solubility and a positive Gibs change value, the conductive oxygen absorbing layer 22 can well adsorb the oxygen in the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30. Furthermore, since the conductive oxygen absorbing layer 22 can absorb oxygen in the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30, and the oxygen vacancies in the ferroelectric storage layer 30 serve as oxygen transmission channels, the oxygen vacancies in the ferroelectric storage layer 30 tend to migrate toward the oxide, thereby adjusting the distribution gradient of the oxygen vacancies in the ferroelectric storage layer 30, so that the direction of the composite electrode 20 pointing to the first electrode 10 (such as Figure 4The density of oxygen vacancies in the ferroelectric storage layer 30 gradually increases, which can also inhibit the continued formation of the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30; of course, the first electrode 10 can play a certain chemical decomposition effect on the oxide layer m0, which can also inhibit the continued formation of the oxide layer m0, thereby further improving the performance of the ferroelectric memory cell.

[0043] In this ferroelectric memory cell, the conductive oxygen absorbing layer 22 may be made of at least one of yttrium, titanium, lanthanum, scandium, copper, aluminum, tantalum, and hafnium. Of course, other materials that can realize the conductive oxygen absorbing layer 22 are also applicable in the embodiment of the present application. In addition, the thickness of the conductive oxygen absorbing layer 22 (e.g. Figure 3 The conductive buffer layer 21 may be made of at least one of TiN and TaN. Of course, other materials that can realize the function of the conductive buffer layer 21 are also applicable in the embodiment of the present application. In addition, the thickness of the conductive buffer layer 21 (as shown in d1 in FIG. 1 ) can be set to 0.5 nm to 5 nm, so that when the thickness of the oxide layer m0 is reduced, the overall thickness of the ferroelectric memory cell can be prevented from being too large, thereby preventing the volume of the ferroelectric memory cell from being increased. The conductive buffer layer 21 may be made of at least one of TiN and TaN. Of course, other materials that can realize the function of the conductive buffer layer 21 are also applicable in the embodiment of the present application. In addition, the thickness of the conductive buffer layer 21 (as shown in FIG. 1 ) can be set to 0.5 nm to 5 nm. Figure 3 d2 in the figure) can be set to 1nm to 20nm, so that when the conductive oxygen absorbing layer 22 is prevented from directly contacting the ferroelectric storage layer 30, the overall thickness of the ferroelectric storage unit can also be avoided to be large. The manufacturing material of the second electrode 23 includes a conductive material, and the conductive material does not contain oxygen, so that the conductive oxygen absorbing layer 22 can fully absorb the oxygen in the oxide layer m0 between the first electrode 10 and the ferroelectric storage layer 30, and the effect of thinning the thickness of the oxide layer m0 is maximized; and the thickness of the first electrode 10 can be set to 1nm to 100nm, and the thickness of the second electrode 23 can be set to 30nm to 100nm, so that the first electrode 10 and the second electrode 23 can withstand the effect of external force, which is conducive to the formation of the ferroelectric phase in the ferroelectric storage layer 30.

[0044] The material of the ferroelectric storage layer 30 may be a doped hafnium oxide material. For example, the material of the ferroelectric storage layer 30 may include: zirconium-doped hafnium oxide (such as Hf 0.5 Zr 0.5 O2), zirconium and lanthanum doped hafnium oxide (such as La doped Hf 0.5 Zr 0.5 O2), zirconium and yttrium-doped hafnium oxide (such as Y-doped Hf 0.5 Zr 0.5 O2), zirconium and strontium doped hafnium oxide (such as Sr doped Hf 0.5 Zr 0.5 O2), zirconium and gadolinium-doped hafnium oxide (such as Gd-doped Hf 0.5 Zr0.5 O2), zirconium, gadolinium, and lanthanum-doped hafnium oxide (such as Gd / La co-doped Hf 0.5 Zr 0.5 O2), silicon-doped hafnium oxide (such as Si-doped HfO2), aluminum-doped hafnium oxide, lanthanum-doped hafnium oxide, yttrium-doped hafnium oxide, gadolinium-doped hafnium oxide, strontium-doped hafnium oxide, etc. In addition, the thickness of the ferroelectric storage layer 30 (such as Figure 3 The thickness of the ferroelectric storage layer 30 is set within a suitable range. On the one hand, it can be beneficial to the formation of the ferroelectric phase and avoid the ferroelectric phase being difficult to form due to the ferroelectric storage layer 30 being too thick. On the other hand, it can avoid the overall thickness of the ferroelectric storage unit being too large, thereby avoiding an increase in the volume of the ferroelectric storage unit.

[0045] The first electrode 10 can be made of conductive metal, metal oxide, metal nitride and other materials, and the first electrode 10 can include one or more metal elements. When the first electrode 10 includes multiple metals, the Gibs of the oxide corresponding to the conductive oxygen absorbing layer 22 is smaller than the Gibs of the oxide corresponding to each metal included in the first electrode 10, so that the conductive oxygen absorbing layer 22 can absorb oxygen in the oxide corresponding to each metal in the first electrode 10, thereby reducing the thickness of the oxide between the first electrode 10 and the ferroelectric storage layer 30, further improving the retention characteristics and weakening the imprinting effect, and improving the performance of the ferroelectric storage unit.

[0046] Exemplarily, the ferroelectric memory cell may include: a transistor and a storage capacitor. The storage solution provided in the embodiment of the present application may be applied to the storage capacitor, that is, the first electrode 10, the ferroelectric storage layer 30 and the composite electrode 20 may form a storage capacitor. Moreover, when the ferroelectric memory cell is disposed on a substrate, the first electrode 10, the ferroelectric storage layer 30 and the composite electrode 20 may be stacked in a direction perpendicular to the surface of the substrate, and the ferroelectric storage layer 30 is disposed between the first electrode 10 and the composite electrode 20. In this case, the storage capacitor may be regarded as a storage capacitor having a two-dimensional structure.

[0047] Figure 5 The schematic diagram of the structure of the storage unit in the embodiment of the present application is shown as an example. Figure 5As shown, the structure of the ferroelectric memory cell in this embodiment is basically similar to that of the ferroelectric memory cell in the first embodiment, except that the structure of the composite electrode 20 is different. Exemplarily, the composite electrode 20 may also include: a conductive adhesive layer 24 disposed between the conductive oxygen absorbing layer 22 and the second electrode 23, the conductive adhesive layer 24 may increase the adhesion strength between the conductive oxygen absorbing layer 22 and the second electrode 23, and avoid the conductive oxygen absorbing layer 22 and the second electrode 23 from falling off, thereby improving the reliability of the ferroelectric memory cell. Among them, the manufacturing material of the conductive adhesive layer 24 may include at least one of TiN and TaN, and of course other materials that can realize the function of the conductive adhesive layer 24 are also applicable in the embodiment of the present application. In addition, the thickness d4 of the conductive adhesive layer 24 may be set to 1nm to 20nm. Setting the thickness of the conductive adhesive layer 24 within a suitable range can, on the one hand, increase the adhesion strength between the conductive oxygen absorbing layer 22 and the second electrode 23, and on the other hand, avoid the overall thickness of the ferroelectric memory cell being too large, thereby avoiding increasing the volume of the ferroelectric memory cell.

[0048] It should be understood that the similarities between the structures of the ferroelectric memory cell in this embodiment and the ferroelectric memory cell in the aforementioned first embodiment can be found in the aforementioned first embodiment, and the repeated parts will not be repeated.

[0049] Figure 6 The schematic diagram of the structure of the storage unit in the embodiment of the present application is shown as an example. Figure 6 As shown in FIG. 1 , (b) is a cross-sectional view along the direction indicated by X1-X2 in (a). The structure of the ferroelectric memory cell in this embodiment is basically similar to that of the ferroelectric memory cell in the first embodiment, except that the storage capacitor is a three-dimensional structure. Exemplarily, the first electrode 10 and the insulating layer m1 can be arranged along a direction perpendicular to the surface of the substrate 40 (e.g. Figure 6 The stacking structure m2 is formed by alternately stacking the stacking structure m2 and then digging a through hole T in the stacking structure m2. The through hole T is arranged along the stacking direction (as shown in the z direction). Figure 6 The stacked structure m2 is penetrated by a ferroelectric storage layer 30 and a composite electrode 20, and then the ferroelectric storage layer 30 is sequentially filled in the through hole T. The ferroelectric storage layer 30 is arranged between the stacked structure m2 and the composite electrode 20. At this time, the stacking direction of the conductive buffer layer 21, the conductive oxygen absorbing layer 22 and the second electrode 23 in the composite electrode 20 (as shown in the z direction) is Figure 6 The x direction or y direction shown in FIG. 1 ) and the extending direction of the through hole T (as shown in FIG. Figure 6 The storage capacitor formed at this time can be regarded as a storage capacitor with a three-dimensional structure. As a result, the ferroelectric memory cell can be a two-dimensional structure as well as a three-dimensional structure, which expands the application range of the ferroelectric memory cell. Figure 7 As shown, Figure 7 For along Figure 6 Another cross-sectional view in the direction shown by X1-X2 in (a), the ferroelectric storage layer 30, the composite electrode 20 and the filling layer 50 can fill the through hole T, and the filling layer 50 is arranged on the side of the composite electrode 20 away from the ferroelectric storage layer 30, that is, the filling layer 50 is located on the side of the second electrode 23 away from the conductive oxygen absorbing layer 22, and the filling layer 50 can be made of insulating material, which can reduce the manufacturing material of the composite electrode 20. When the cost of the manufacturing material of the composite electrode 20 is high and the cost of the manufacturing material of the filling layer 50 is low, the manufacturing cost of the ferroelectric storage unit can be effectively reduced. Alternatively, see Figure 6 As shown, the ferroelectric memory layer 30 and the composite electrode 20 can fill the through hole T, that is, the composite electrode 20 fills the space in the through hole T not occupied by the ferroelectric memory layer 30, which can simplify the manufacturing steps and manufacturing process of the ferroelectric memory unit and improve the manufacturing efficiency.

[0050] It should be understood that the similarities between the structures of the ferroelectric memory cell in this embodiment and the ferroelectric memory cell in the aforementioned first embodiment can be found in the aforementioned first embodiment, and the repeated parts will not be repeated.

[0051] Figure 8 FIG. 1 is a schematic diagram of a first method for manufacturing a ferroelectric memory cell in an embodiment of the present application. This embodiment is given by applying it to a storage capacitor, and the storage capacitor is a two-dimensional structure. Figure 8 As shown, the specific manufacturing process of the ferroelectric memory cell may include:

[0052] Step 1: Figure 8 As shown in (a), a chemical vapor deposition method is used, using but not limited to metal W, to deposit a W film layer with a thickness of about 50 nm on the substrate to form a first electrode;

[0053] Step 2: If Figure 8 As shown in (b), an atomic layer vapor deposition method is used, using but not limited to zirconium-doped hafnium oxide material, to deposit a HZO layer with a thickness of about 10 nm on the first electrode to form a ferroelectric storage layer;

[0054] In the zirconium-doped hafnium oxide material, the molar ratio of zirconium to hafnium is 1:1, but is not limited to 1:1. This is just used as an example for illustration.

[0055] Step 3: If Figure 8 As shown in (c), an atomic layer vapor deposition method is used, using but not limited to TiN, to deposit a TiN layer with a thickness of about 5 nm on the ferroelectric storage layer to form a conductive buffer layer;

[0056] Step 4: Figure 8As shown in (d), a physical vapor deposition method is used, using but not limited to metal Y (Chinese name is yttrium), and a Y film layer with a thickness of about 3 nm is deposited on the conductive buffer layer to form a conductive oxygen absorption layer, so that the Gibbs free energy of the oxide corresponding to the conductive oxygen absorption layer (i.e., yttrium oxide) is less than the Gibbs free energy of the oxide corresponding to the first electrode (i.e., tungsten oxide);

[0057] Step 5: Figure 8 As shown in (e), a chemical vapor deposition method is used, using but not limited to metal W, to deposit a W film layer with a thickness of about 50 nm on the conductive oxygen absorbing layer to form a second electrode, so that the conductive buffer layer, the conductive oxygen absorbing layer and the second electrode form a composite electrode;

[0058] Step 6: heat-treating the structure obtained in step 5 so that the ferroelectric storage layer exhibits ferroelectric properties.

[0059] It should be understood that in the above steps 1 to 5, the materials used and the thickness of each film layer are not limited to those listed in this embodiment. This is just an example for explanation. Other materials and other film layer thicknesses can be selected according to actual needs and are not limited here. Figure 8 In the figure, the thickness of each film layer shown does not represent the actual thickness of the film layer produced. It only shows the positional relationship between the film layers and does not represent the actual size of the film layer.

[0060] Fig. 9 FIG. 1 is a schematic diagram showing a second method for manufacturing a ferroelectric memory cell according to an embodiment of the present application. Fig. 9 As shown, the second manufacturing method in this embodiment is basically similar to the first manufacturing method in the above embodiment, except that: step s1 is added between step 4 and step 5. Specifically, step s1 may include: Fig. 9 As shown in (e), an atomic layer vapor deposition method is used, using but not limited to TiN, to deposit a TiN layer with a thickness of about 5 nm on the conductive oxygen absorbing layer to form a conductive adhesion layer. The conductive adhesion layer can increase the adhesion strength between the conductive oxygen absorbing layer and the second electrode, and prevent the conductive oxygen absorbing layer from falling off from the second electrode, thereby improving the reliability of the ferroelectric memory cell. Further, step 5 in the above embodiment can be adaptively adjusted as follows: Fig. 9 As shown in (f), a chemical vapor deposition method is used, using but not limited to metal W, to deposit a W film layer with a thickness of about 50 nm on the conductive adhesion layer to form a second electrode, so that the conductive buffer layer, the conductive oxygen absorption layer, the conductive adhesion layer and the second electrode form a composite electrode.

[0061] It should be understood that the similarities between the second manufacturing method in this embodiment and the first manufacturing method in the aforementioned embodiment can be referred to the first manufacturing method in the aforementioned embodiment, and the repeated parts will not be repeated.

[0062] Fig.10 FIG. 1 is a schematic diagram showing a third method for manufacturing a ferroelectric memory cell according to an embodiment of the present application. Fig.10 As shown, the third manufacturing method in this embodiment is basically similar to the first manufacturing method in the above-mentioned embodiment, and the differences include:

[0063] (1) Adjust the above step 1 to: Fig.10 As shown in (a), a metal W film layer and an insulating layer are alternately deposited on a substrate by chemical vapor deposition to obtain a stacked structure m2, and the metal W film layer is used as a first electrode; wherein the stacked structure m2 includes multiple first electrodes and multiple insulating layers;

[0064] (2) Add step s2 between the above steps 1 and 2. Step s2 may include: Fig.10 As shown in (b), the stacked structure m2 is opened by photolithography and high aspect ratio dry etching to obtain a columnar through hole T with a diameter of about 50 nm, and the through hole T penetrates the stacked structure m2 along the stacking direction;

[0065] (3) Each film layer formed in the above steps 2 to 5 is made in the through hole T, such as Fig.10 As shown in (c) and (d);

[0066] (4) The material of the conductive oxygen absorbing layer in step 4 is adjusted to titanium aluminum alloy, i.e., TiAl;

[0067] (5) If the second electrode formed in the above step 5 does not fill the remaining space in the through hole T, it is necessary to continue to form a filling layer after forming the second electrode, and fill the unoccupied space in the through hole T with the filling layer, which is not shown in the figure; wherein the filling layer manufacturing process includes: using chemical vapor deposition method, using insulating material, depositing an insulating layer m1 on the second electrode to fill the through hole T; wherein the insulating material and the manufacturing material of the insulating layer m1 can be the same or different.

[0068] In this way, the storage capacitor obtained is a three-dimensional structure, which expands the application range of the ferroelectric memory cell.

[0069] It should be understood that the similarities between the third manufacturing method in this embodiment and the first manufacturing method in the aforementioned embodiment can be referred to the first manufacturing method in the aforementioned embodiment, and the repeated parts will not be repeated.

[0070] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A ferroelectric memory cell, characterized in that: include: A first electrode, a composite electrode, and a ferroelectric storage layer arranged between the first electrode and the composite electrode, wherein the composite electrode comprises: a conductive buffer layer, a conductive oxygen absorption layer, and a second electrode arranged in sequence along a direction pointing from the first electrode to the ferroelectric storage layer; wherein the Gibbs free energy of the oxide corresponding to the conductive oxygen absorption layer is less than the Gibbs free energy of the oxide corresponding to the first electrode.

2. The ferroelectric memory cell according to claim 1, wherein: The conductive buffer layer is made of at least one of TiN and TaN.

3. The ferroelectric memory cell according to claim 1 or 2, characterized in that: The thickness of the conductive buffer layer is 1 nm-20 nm.

4. The ferroelectric memory cell according to any one of claims 1 to 3, characterized in that: The conductive oxygen absorbing layer is made of at least one of yttrium, titanium, lanthanum, scandium, copper, aluminum, tantalum and hafnium.

5. The ferroelectric memory cell according to any one of claims 1 to 4, characterized in that: The thickness of the conductive oxygen absorbing layer is 0.5 nm to 5 nm.

6. The ferroelectric memory cell according to any one of claims 1 to 5, characterized in that: The thickness of the second electrode is 30 nm to 100 nm.

7. The ferroelectric memory cell according to any one of claims 1 to 6, characterized in that: The second electrode is made of a conductive material, which does not contain oxygen.

8. The ferroelectric memory cell according to any one of claims 1 to 7, characterized in that: The composite electrode further comprises: a conductive adhesion layer disposed between the conductive oxygen absorbing layer and the second electrode.

9. The ferroelectric memory cell according to claim 8, characterized in that The conductive adhesion layer is made of at least one of TiN and TaN.

10. A method for manufacturing a ferroelectric memory cell according to any one of claims 1 to 9, characterized in that: include: forming a first electrode; forming a ferroelectric storage layer on the first electrode; forming a conductive buffer layer on the ferroelectric storage layer; forming a conductive oxygen absorption layer on the conductive buffer layer, wherein the Gibbs free energy of the oxide corresponding to the conductive oxygen absorption layer is smaller than the Gibbs free energy of the oxide corresponding to the first electrode; A second electrode is formed on the conductive oxygen absorbing layer, so that the conductive buffer layer, the conductive oxygen absorbing layer and the second electrode form a composite electrode.

11. The method according to claim 10, characterized in that: Also includes: After forming the conductive oxygen gettering layer and before forming the second electrode, a conductive adhesive layer is formed on the conductive oxygen gettering layer.

12. A ferroelectric memory, characterized in that: include: A storage array and a controller coupled to the storage array, wherein the storage array includes a plurality of ferroelectric memory cells according to any one of claims 1 to 9, and the plurality of ferroelectric memory cells are arranged in an array manner; The storage array is used to store data; The controller is used to write data into the storage array or read data from the storage array.

13. An electronic device, characterized in that: include: A circuit board and a ferroelectric memory as claimed in claim 12, wherein the ferroelectric memory is arranged on the circuit board.

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