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

Abstract

The invention provides a memory cell, a manufacturing method thereof, a ferroelectric memory and electronic equipment, which are used for improving the performance of the ferroelectric memory. The storage unit comprises a first electrode, a second electrode and a ferroelectric layer, and the ferroelectric layer is located between the first electrode and the second electrode. The oxygen vacancy concentration in the ferroelectric layer is in gradient distribution in the first direction, and the first direction is the direction from the first electrode to the second electrode. According to the embodiment of the invention, the oxygen vacancy concentration in the ferroelectric layer is set to be in gradient distribution in the first direction, and the polarization orientation of the ferroelectric phase can be distributed along the first direction, so that the randomness of the polarization orientation is greatly reduced, the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer is improved, and the performance of the ferroelectric memory is improved.

Description

Technical Field

[0001] This application relates to the field of storage technologies, and particularly to a storage cell, a method for manufacturing the same, a ferroelectric memory, and an electronic device. Background Art

[0002] Memories can be classified into volatile memories and non-volatile memories. Among them, volatile dynamic random access memories (DRAMs) have advantages such as fast read / write speeds and strong durability. However, dynamic random access memories have small storage capacities and high power consumptions. With the rapid development of the Internet of Things, big data, and artificial intelligence, traditional dynamic random access memories can no longer meet the requirements.

[0003] New ferroelectric memories have advantages such as fast speeds, good durability, and non-volatility. Their performance in terms of storage capacity, power consumption, rate, etc. has been greatly improved compared to traditional dynamic random access memories. Among them, hafnium oxide-based ferroelectric memories have superior polarization characteristics, good size scalability, and high compatibility with complementary metal oxide semiconductor (CMOS) processes, and have broad application prospects in the field of next-generation high-integration, low-power devices.

[0004] However, hafnium oxide thin films prepared by the industrially mature atomic layer deposition (ALD) process naturally exhibit a polycrystalline structural state, and neither the crystal phase nor the crystal orientation can be unified. Under current process conditions, most hafnium oxide thin films coexist with a ferroelectric phase (O-phase) and other non-ferroelectric phases, and the polarization orientations of the ferroelectric phases are randomly distributed. This will seriously affect the performance of hafnium oxide-based ferroelectric memories and restrict the further optimization and improvement of their performance. Summary of the Invention

[0005] Embodiments of this application provide a storage cell, a method for manufacturing the same, a ferroelectric memory, and an electronic device to improve the performance of ferroelectric memories.

[0006] In a first aspect, embodiments of this application provide a storage cell. The storage cell provided by the embodiments of this application may include: a first electrode, a second electrode, and a ferroelectric layer, where the ferroelectric layer is located between the first electrode and the second electrode. The oxygen vacancy concentration in the ferroelectric layer is distributed in a gradient manner in a first direction. Here, the first direction is the direction from the first electrode to the second electrode. In the embodiments of this application, the oxygen vacancy concentration in the ferroelectric layer being distributed in a gradient manner in the first direction can be understood as: there is a concentration difference in the oxygen vacancies in the ferroelectric layer in the first direction.

[0007] Since the oxygen vacancy concentration distribution in the ferroelectric layer is correlated with the polarization orientation of the ferroelectric phase, the built-in electric field formed by the oxygen vacancy concentration difference has a strong templating effect on the polarization orientation. Therefore, in the embodiments of the present application, setting the oxygen vacancy concentration in the ferroelectric layer to be gradient-distributed in the first direction can form a built-in electric field consistent with the first direction. The formed built-in electric field can directly affect the polarization orientation of the ferroelectric phase, making the polarization orientation of the ferroelectric phase also distributed along the first direction, thereby greatly reducing the randomness of the polarization orientation and improving the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer, and further improving the performance of the ferroelectric memory.

[0008] The storage unit in the embodiments of the present application can be a hafnium oxide-based ferroelectric storage unit, that is, the above ferroelectric layer can include hafnium oxide materials. For example, the ferroelectric layer can include zirconium-doped hafnium oxide (HfxZr1-xO, HZO) materials. Of course, in some cases, the storage unit in the embodiments of the present application can also be a ferroelectric storage unit including other ferroelectric materials.

[0009] In specific implementation, the storage unit in the embodiments of the present application can further include: a substrate, which can play a role in carrying the first electrode, the second electrode, and the ferroelectric layer. In the embodiments of the present application, the first electrode can be located between the substrate and the ferroelectric layer, and the second electrode can be located on the side of the ferroelectric layer away from the substrate. In some cases, the positions of the first electrode and the second electrode can be interchanged and set according to actual needs.

[0010] The basic structure of the storage unit in the embodiments of the present application is introduced above. The following details the specific embodiments of the storage unit in the embodiments of the present application.

[0011] Embodiment 1:

[0012] In some embodiments of the present application, the first electrode and the second electrode can have different oxygen vacancy generation energies, and the oxygen vacancy concentration at the first interface of the ferroelectric layer is different from that at the second interface. Among them, the first interface is the interface where the ferroelectric layer contacts the first electrode, and the second interface is the interface where the ferroelectric layer contacts the second electrode. By setting the first electrode and the second electrode to have different oxygen vacancy generation energies, the oxygen vacancy concentration difference can be formed at the first interface and the second interface of the ferroelectric layer, so that the oxygen vacancy concentration in the ferroelectric layer is gradient-distributed in the first direction, thereby forming a uniform built-in electric field inside the ferroelectric layer, and further improving the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer and the performance of the ferroelectric memory.

[0013] During the manufacturing process, different chemical ratios can be used to fabricate the first electrode and the second electrode. A dangling bond capable of absorbing oxygen can be formed in one of the electrodes, so that the first electrode and the second electrode have different oxygen vacancy formation energies. Taking the formation of a dangling bond capable of absorbing oxygen in the second electrode as an example, after the first electrode, the ferroelectric layer, and the second electrode are sequentially formed on the substrate, an annealing process is used to treat the ferroelectric layer to crystallize the ferroelectric material in the ferroelectric layer. For example, a rapid thermal annealing process can be used to treat the ferroelectric layer. During the annealing process, the dangling bonds in the second electrode can absorb oxygen atoms in the ferroelectric layer, causing more oxygen vacancies to form at the second interface of the ferroelectric layer. Conversely, the first electrode will result in fewer oxygen vacancies at the first interface of the ferroelectric layer. Thus, a concentration difference in oxygen vacancies can be formed at the first interface and the second interface of the ferroelectric layer to form a uniform built-in electric field in the ferroelectric layer. In specific implementation, the chemical ratios of the first electrode and the second electrode can be reasonably set according to the specific materials of the first electrode and the second electrode.

[0014] In a possible implementation, both the first electrode and the second electrode can include compound materials. Specifically, both the first electrode and the second electrode can include: a first element and a second element, where the first element is a metal element and the second element is a non-metal element. The atomic count ratio of the first element to the second element in the first electrode is different from the atomic count ratio of the first element to the second element in the second electrode. In this way, the oxygen vacancy formation energies of the first electrode and the second electrode can be made different. During the manufacturing process, different chemical ratios can be used to fabricate the first electrode and the second electrode so that the atomic count ratios of the first element to the second element in the fabricated first electrode and second electrode are different. Exemplarily, the first element can be elements such as Ti, Ta, Al, etc., and the second element can be elements such as N, P, As, etc. Optionally, the first electrode can include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN, and the second electrode can include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN.

[0015] In one embodiment, the materials of the first electrode and the second electrode can be the same. For example, both the first electrode and the second electrode can include TiN material, or both the first electrode and the second electrode can include TaN material. In another embodiment, the materials of the first electrode and the second electrode can also be different. Exemplarily, the first electrode can include TiN material and the second electrode can include TaN material; or the first electrode can include TiAlN material and the second electrode can include TiN material. In specific implementation, the materials of the first electrode and the second electrode can be set according to actual needs, and no further examples will be given here.

[0016] In another possible implementation, the first electrode may include a metallic material, and the second electrode may include a compound material. For example, the first electrode may include metallic materials such as metal W, Al, Cu, etc., and the second electrode may include: a first element and a second element, where the first element is a metallic element and the second element is a non-metallic element. Exemplarily, the first element may be other metallic elements such as Ti, Ta, Al, etc., and the second element may also include other non-metallic materials such as N, P, As, etc. There may be dangling bonds of the first element in the second electrode; or, there may be dangling bonds of the second element in the second electrode. In this way, the oxygen vacancy concentration at the first interface and the second interface of the ferroelectric layer can also be made different.

[0017] Embodiment 2:

[0018] In some other embodiments of the present application, the ferroelectric layer may include at least two ferroelectric thin films stacked on top of each other, and the oxygen vacancy concentration in adjacent two ferroelectric thin films is different. In practical applications, the number of ferroelectric thin films in the ferroelectric layer and the distribution law of the oxygen vacancy concentration can be set according to actual needs. In the embodiments of the present application, by setting at least two stacked ferroelectric thin films and having different oxygen vacancy concentrations in adjacent two ferroelectric thin films, the oxygen vacancy concentration in the ferroelectric layer can be made to have a gradient distribution (or called a chain distribution), so that a uniform built-in electric field can be formed in the ferroelectric layer, and the direction of the built-in electric field is consistent with the first direction, and further the polarization direction of the ferroelectric phase is also arranged along the first direction.

[0019] During the manufacturing process, the atomic layer deposition (ALD) process can be used to fabricate each ferroelectric thin film in the ferroelectric layer. During the deposition of each ferroelectric thin film, ferroelectric thin films with different oxygen vacancy concentrations can be formed by controlling the dose of oxygen element (O-dose). Specifically, the dose of oxygen element can be adjusted by controlling parameters such as the residence time, concentration, or flow rate of the oxygen element. Exemplarily, when the ferroelectric layer includes hafnium zirconium oxide (HfxZr1-xO, HZO) material, the oxygen vacancy concentration in the ferroelectric thin film can be controlled by adjusting parameters such as the residence time, concentration, or flow rate of oxygen (O) element, zirconium (Zr) element, and hafnium (Hf) element.

[0020] In the embodiments of the present application, the thickness of the ferroelectric layer can be in the range of 5 nm to 15 nm. For example, the thickness of the ferroelectric layer can be 5 nm, 8 nm, 10 nm, 12 nm, or 15 nm, etc. The thickness of a single ferroelectric thin film can be in the range of 0.5 nm to 2 nm. For example, the thickness of the ferroelectric thin film can be 0.5 nm, 1 nm, 1.5 nm, or 2 nm, etc.

[0021] In a possible implementation, the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer may be alternately distributed in a high-low pattern in the first direction. For example, the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer may be distributed in a pattern of low-high-low-high-low-high or high-low-high-low-high-low in the first direction. In another possible implementation, the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer may be distributed in a pattern of first decreasing and then increasing or first increasing and then decreasing in the first direction. In practical applications, the number of ferroelectric thin films in the ferroelectric layer and the distribution pattern of the oxygen vacancy concentration can be set according to actual needs.

[0022] In a second aspect, an embodiment of the present application further provides a method for manufacturing a storage cell. The method for manufacturing a storage cell provided by the embodiment of the present application may include:

[0023] Step 1: Form a first electrode on a substrate;

[0024] Step 2: Deposit a ferroelectric layer on the first electrode;

[0025] Step 3: Form a second electrode on the ferroelectric layer; the first electrode and the second electrode have different oxygen vacancy generation energies;

[0026] Step 4: Use an annealing process to treat the ferroelectric layer so that the oxygen elements in the ferroelectric layer move in the first direction, so that the oxygen vacancy concentration in the ferroelectric layer is distributed in a gradient in the first direction, and the first direction is the direction from the first electrode to the second electrode.

[0027] In the embodiment of the present application, by fabricating the first electrode and the second electrode with different oxygen vacancy generation energies, during the subsequent annealing process, the electrode with a higher oxygen vacancy generation energy can absorb the oxygen elements in the ferroelectric layer, so that the oxygen elements in the ferroelectric layer move in the first direction, so that the oxygen vacancy concentration in the ferroelectric layer is distributed in a gradient in the first direction, thereby forming a uniform built-in electric field inside the ferroelectric layer, and further improving the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer and improving the performance of the ferroelectric memory.

[0028] The storage cell in the embodiment of the present application may be a hafnium oxide-based ferroelectric storage cell. In step 2 above, a hafnium oxide material may be used to fabricate the ferroelectric layer. For example, a hafnium zirconium oxide (HfxZr1-xO, HZO) material may be used to fabricate the ferroelectric layer. Of course, in some cases, other ferroelectric materials may also be used to fabricate the ferroelectric layer. In a possible implementation, an atomic layer deposition (ALD) process may be used to fabricate the ferroelectric layer.

[0029] In the above-mentioned step one and step three, different chemical ratios can be used to fabricate the first electrode and the second electrode, and dangling bonds capable of absorbing oxygen are formed in one of the electrodes, so that the first electrode and the second electrode have different oxygen vacancy formation energies. Taking the formation of dangling bonds capable of absorbing oxygen in the second electrode as an example, in the above-mentioned step four, an annealing process is used to treat the ferroelectric layer to crystallize the ferroelectric material in the ferroelectric layer. For example, a rapid thermal annealing process can be used to treat the ferroelectric layer. During the annealing process, the dangling bonds in the second electrode can absorb oxygen atoms in the ferroelectric layer, causing the ferroelectric layer to form more oxygen vacancies at the second interface. On the contrary, the first electrode will result in fewer oxygen vacancies at the first interface of the ferroelectric layer. Thus, a difference in oxygen vacancy concentration can be formed at the first interface and the second interface of the ferroelectric layer to form a uniform built-in electric field in the ferroelectric layer.

[0030] The manufacturing method in the second aspect can fabricate the storage unit of Embodiment 1 in the first aspect above. For the specific implementation manner of the manufacturing method in the second aspect, reference can be made to the specific implementation manner of the storage unit of Embodiment 1 in the first aspect above, and the repeated parts will not be elaborated.

[0031] In a third aspect, an embodiment of the present application further provides a manufacturing method of a storage unit. The manufacturing method of the storage unit provided by the embodiment of the present application may include:

[0032] Step (1), forming a first electrode on a substrate;

[0033] Step (2), sequentially depositing at least two ferroelectric thin films on the first electrode, and making the oxygen vacancy concentrations in adjacent two ferroelectric thin films different;

[0034] Step (3), forming a second electrode on the at least two ferroelectric thin films.

[0035] In the embodiment of the present application, by sequentially depositing at least two ferroelectric thin films on the first electrode and making the oxygen vacancy concentrations in adjacent two ferroelectric thin films different, the oxygen vacancy concentration in the ferroelectric layer can be distributed in a gradient manner, so that a uniform built-in electric field can be formed in the ferroelectric layer. The direction of the built-in electric field is consistent with the first direction (the direction from the first electrode to the second electrode), and further induces the polarization direction of the ferroelectric phase to also be arranged along the first direction.

[0036] The storage unit in the embodiment of the present application can be a hafnium oxide-based ferroelectric storage unit. In the above-mentioned step (2), hafnium oxide materials can be used to fabricate each ferroelectric thin film in the ferroelectric layer. For example, hafnium zirconium oxide (HfxZr1-xO, HZO) materials can be used to fabricate the ferroelectric thin film. Of course, in some cases, other ferroelectric materials can also be used to fabricate the ferroelectric thin film.

[0037] In step (ii) above, an atomic layer deposition (ALD) process can be used to fabricate each ferroelectric thin film. During the deposition of each ferroelectric thin film, ferroelectric thin films with different oxygen vacancy concentrations can be formed by controlling the dose of oxygen element (O-dose). Specifically, the dose of oxygen element can be adjusted by controlling parameters such as the residence time, concentration, or flow rate of oxygen element. Exemplarily, when the ferroelectric layer includes a hafnium zirconium oxide (HfxZr1-xO, HZO) material, the oxygen vacancy concentration in the ferroelectric thin film can be controlled by adjusting parameters such as the residence time, concentration, or flow rate of oxygen (O) element, zirconium (Zr) element, and hafnium (Hf) element.

[0038] Specifically, in step (ii) above, the thickness of the deposited single-layer ferroelectric thin film can be in the range of 0.5 nm to 2 nm. For example, the thickness of the ferroelectric thin film can be 0.5 nm, 1 nm, 1.5 nm, or 2 nm, etc. The total thickness of the ferroelectric layer obtained by stacking each ferroelectric thin film can be in the range of 5 nm to 15 nm. For example, the total thickness of the ferroelectric layer can be 5 nm, 8 nm, 10 nm, 12 nm, or 15 nm, etc.

[0039] In one possible implementation, the oxygen vacancy concentrations of the ferroelectric thin films in the ferroelectric layer can be alternately distributed in a high-low pattern in the first direction. For example, the oxygen vacancy concentrations of the ferroelectric thin films in the ferroelectric layer can be regularly distributed in a low-high-low-high-low-high or high-low-high-low-high-low pattern in the first direction. In another possible implementation, the oxygen vacancy concentrations of the ferroelectric thin films in the ferroelectric layer can be regularly distributed in a pattern of first decreasing and then increasing or first increasing and then decreasing in the first direction. In practical applications, the number of ferroelectric thin films in the ferroelectric layer and the distribution pattern of the oxygen vacancy concentration can be set according to actual needs.

[0040] The storage unit of Embodiment 2 in the first aspect above can be fabricated by using the fabrication method in the third aspect. The specific implementation of the fabrication method in the third aspect can be implemented with reference to the specific implementation of the storage unit of Embodiment 2 in the first aspect above, and the repeated parts will not be elaborated.

[0041] Fourth aspect, embodiments of the present application further provide a ferroelectric memory. The ferroelectric memory in the embodiments of the present application may be a hafnium oxide-based ferroelectric memory. Of course, the ferroelectric memory in the embodiments of the present application may also be a ferroelectric memory including other ferroelectric materials. The ferroelectric memory in the embodiments of the present application may be various types of memories such as ferroelectric random access memory (FeRAM or FRAM), ferroelectric field effect transistor (FeFET) memory, or ferroelectric tunneling junction (FTJ) memory.

[0042] The ferroelectric memory provided by the embodiments of the present application may include: a controller and any one of the storage units in the first aspect above, and the storage unit is electrically connected to the controller. Since the polarization orientation of the ferroelectric phase in the storage unit in the first aspect above has a relatively high uniformity, the performance of the ferroelectric memory including the above storage unit is better.

[0043] Fifth aspect, embodiments of the present application further provide an electronic device. The electronic device in the embodiments of the present application may be any electronic device with a storage function. For example, the electronic device in the embodiments of the present application may be a mobile phone, a tablet computer, a desktop computer, a smart wearable device, a vehicle-mounted device, a server, a processor, etc.

[0044] The electronic device provided by the embodiments of the present application may include: a circuit board and any one of the ferroelectric memories in the fourth aspect above, and the ferroelectric memory is electrically connected to the circuit board. Since the performance of the ferroelectric memory in the fourth aspect above is relatively high, the performance of the electronic device including the above ferroelectric memory is also better. Description of the Drawings

[0045] Figure 1 It is a schematic structural diagram of the storage unit provided by the embodiments of the present application;

[0046] Figure 2 It is a schematic comparison diagram of the relationship between the oxygen vacancy concentration distribution and the polarization orientation of the ferroelectric domain;

[0047] Figure 3 It is another schematic structural diagram of the storage unit provided by the embodiments of the present application;

[0048] Figure 4 It is a schematic chemical ratio diagram of the first electrode and the second electrode in the embodiments of the present application;

[0049] Figure 5 It is another schematic diagram of the chemical ratio of the first electrode and the second electrode in the embodiments of the present application;

[0050] Figure 6a Another structural schematic diagram of the storage unit provided by the embodiment of the present application;

[0051] Figure 6b A comparative example of the storage unit in the embodiment of the present application;

[0052] Figure 7 A structural schematic diagram of the ferroelectric layer in the embodiment of the present application;

[0053] Figure 8 Another structural schematic diagram of the ferroelectric layer in the embodiment of the present application;

[0054] Figure 9 Another structural schematic diagram of the ferroelectric layer in the embodiment of the present application;

[0055] Figure 10 A flowchart of the manufacturing method of the storage unit provided by the embodiment of the present application;

[0056] Figure 11 Another flowchart of the manufacturing method of the storage unit provided by the embodiment of the present application.

[0057] Reference numerals:

[0058] 10 - Substrate; 11 - First electrode; 12 - Second electrode; 13 - Ferroelectric layer; 131 - Ferroelectric thin film; E - Built-in electric field; P - Polarization orientation; F1 - First direction; Q1 - First interface; Q2 - Second interface. Detailed implementation manners

[0059] The novel ferroelectric memory has the advantages of fast speed, good durability, non-volatility, etc., and its performance such as storage capacity, power consumption and rate has been greatly improved compared with the traditional dynamic random access memory. Among them, the hafnium oxide-based ferroelectric memory has excellent polarization characteristics, good size scalability and high compatibility with the complementary metal oxide semiconductor (CMOS) process, and has broad application prospects in the field of next-generation high-integration and low-power devices.

[0060] However, hafnium oxide thin films prepared by using the mature atomic layer deposition (ALD) process in the industry naturally exhibit a polycrystalline structural state, and neither the crystal phase nor the crystal orientation can be unified. Under the current process conditions, most hafnium oxide thin films coexist with a ferroelectric phase (O-phase) and other non-ferroelectric phases, and the polarization orientations of the ferroelectric phases are randomly distributed. As hafnium oxide-based ferroelectric memories gradually develop towards higher integration and miniaturization, the size of hafnium oxide-based ferroelectric memories becomes smaller and smaller, and the uniformity of the polarization orientations of the ferroelectric phases becomes worse and worse. As a result, the threshold voltage differences corresponding to the write (program) operation and the erase operation become smaller and smaller, leading to a smaller discrimination between the write operation and the erase operation, seriously affecting the performance of hafnium oxide-based ferroelectric memories, and restricting the further optimization and improvement of their performance.

[0061] Based on this, the embodiments of the present application provide a storage cell, a manufacturing method thereof, a ferroelectric memory, and an electronic device to improve the performance of the ferroelectric memory. The ferroelectric memory in the embodiments of the present application may be a hafnium oxide-based ferroelectric memory. Of course, the ferroelectric memory in the embodiments of the present application may also be a ferroelectric memory including other ferroelectric materials. The ferroelectric memory in the embodiments of the present application may be various types of memories such as a ferroelectric random access memory (FeRAM or FRAM), a ferroelectric field effect transistor (FeFET) memory, or a ferroelectric tunneling junction (FTJ) memory. The ferroelectric memory provided by the embodiments of the present application can be applied to various electronic devices with storage functions, such as mobile phones, tablet computers, desktop computers, smart wearable devices, vehicle-mounted devices, servers, processors, and other electronic devices.

[0062] 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 with reference to the accompanying drawings.

[0063] It should be noted that the same reference numerals in the drawings of the present application represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing positions and directions described in the present application are all illustrated with reference to the drawings, but can be changed according to needs, and all changes are included in the protection scope of the present application. The drawings of the present application are only used to illustrate the relative position relationship and do not represent the true scale.

[0064] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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 cannot be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0065] Figure 1 The structure diagram of the storage unit provided by the embodiment of the present application is as Figure 1 shown. The storage unit provided by the embodiment of the present application may include: a first electrode 11, a second electrode 12, and a ferroelectric layer 13. The ferroelectric layer 13 is located between the first electrode 11 and the second electrode 12. The oxygen vacancy concentration in the ferroelectric layer 13 is distributed in a gradient in the first direction F1. Wherein, the first direction F1 is the direction from the first electrode 11 to the second electrode 12, and the first direction F1 may be Figure 1 the vertically upward direction shown in Figure 1 or the vertically downward direction. In the embodiment of the present application, the oxygen vacancy concentration in the ferroelectric layer 13 is distributed in a gradient in the first direction F1, which can be understood as: there is a concentration difference of oxygen vacancies in the ferroelectric layer 13 in the first direction F1. For example, in

[0066] the white circles represent oxygen vacancies and the black circles represent oxygen atoms. There are more oxygen vacancies and a higher oxygen vacancy concentration at the position of the ferroelectric layer 13 close to the second electrode 12, and there are more oxygen atoms and a lower oxygen vacancy concentration at the position of the ferroelectric layer 13 close to the first electrode 11. There is a concentration difference of oxygen vacancies in the ferroelectric layer 13 in the first direction F1, and the oxygen vacancy concentration is distributed in a gradient in the first direction F1.

[0067] Figure 2 It is a schematic diagram for comparing the relationship between the oxygen vacancy concentration distribution and the polarization orientation of ferroelectric domains. Figure 2 In (1) of Figure 2 is the schematic diagram of the polarization orientation of ferroelectric domains. Figure 2 In (2) of Figure 2 is the schematic diagram of the oxygen vacancy concentration distribution. As Figure 2As can be seen from (1) in [reference], the polarization orientation P within the same ferroelectric domain is basically consistent, while the polarization orientations P of different ferroelectric domains are random. From Figure 2 As can be seen from (2) in [reference], the oxygen vacancy concentration shows a gradient distribution from high to low (as the filled colors in the figure change from dark to light), and the difference in oxygen vacancy concentration can form a built-in electric field E. Comparing Figure 2 (1) and (2) in [reference], it can be clearly seen that although the polarization orientations P and the distribution of oxygen vacancy concentration of different ferroelectric domains have a certain degree of randomness, the distribution of the polarization orientations P of different ferroelectric domains is basically consistent with the direction of the built-in electric field E in different ferroelectric domains. The built-in electric field E has a strong templating effect on the polarization orientation P. Therefore, the concentration distribution of oxygen vacancies in the ferroelectric phase can directly affect the polarization orientation P.

[0068] Combined with Figure 1 and Figure 2 , since the concentration distribution of oxygen vacancies in the ferroelectric layer 13 is correlated with the polarization orientation P of the ferroelectric phase, the built-in electric field E formed by the difference in oxygen vacancy concentration has a strong templating effect on the polarization orientation P. Therefore, in the embodiments of the present application, setting the oxygen vacancy concentration in the ferroelectric layer 13 to be gradient-distributed in the first direction F1 can form a built-in electric field E that is consistent with the first direction F1. The formed built-in electric field E can directly affect the polarization orientation P of the ferroelectric phase, making the polarization orientation P of the ferroelectric phase also distribute along the first direction F1, thereby greatly reducing the randomness of the polarization orientation P and improving the uniformity of the polarization orientation P of the ferroelectric phase in the ferroelectric layer 13, and further improving the performance of the ferroelectric memory.

[0069] The basic structure of the storage unit in the embodiments of the present application is introduced above. The following will combine the accompanying drawings to elaborate on the specific embodiments of the storage unit in the embodiments of the present application in detail.

[0070] Embodiment 1:

[0071] Figure 3 is another structural schematic diagram of the storage unit provided by the embodiments of the present application, as shown in Figure 3As shown, in some embodiments of the present application, the first electrode 11 and the second electrode 12 may have different oxygen vacancy generation energies, and the oxygen vacancy concentration of the ferroelectric layer 13 at the first interface Q1 is different from that at the second interface Q2. Among them, the first interface Q1 is the interface where the ferroelectric layer 13 contacts the first electrode 11, and the second interface Q2 is the interface where the ferroelectric layer 13 contacts the second electrode 12. By setting the first electrode 11 and the second electrode 12 to have different oxygen vacancy generation energies, an oxygen vacancy concentration difference can be formed at the first interface Q1 and the second interface Q2 of the ferroelectric layer 13, so that the oxygen vacancy concentration in the ferroelectric layer 13 is distributed in a gradient manner in the first direction F1, thereby forming a uniform built-in electric field inside the ferroelectric layer 13, and further improving the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer 13 and improving the performance of the ferroelectric memory.

[0072] In specific implementation, the storage unit in the embodiments of the present application may further include: a substrate 10, and the substrate 10 can play a role in carrying the first electrode 11, the second electrode 12, and the ferroelectric layer 13. In the drawings of the present application, an example is schematically shown with the first electrode 11 located between the substrate 10 and the ferroelectric layer 13, and the second electrode 12 located on the side of the ferroelectric layer 13 away from the substrate 10. In some cases, the positions of the first electrode 11 and the second electrode 12 can be interchanged and set according to actual needs.

[0073] During the manufacturing process, different chemical ratios can be used to manufacture the first electrode 11 and the second electrode 12, and dangling bonds capable of absorbing oxygen are formed in one of the electrodes, so that the first electrode 11 and the second electrode 12 have different oxygen vacancy generation energies. Taking the formation of dangling bonds capable of absorbing oxygen in the second electrode 12 as an example, after the first electrode 11, the ferroelectric layer 13, and the second electrode 12 are sequentially formed on the substrate 10, an annealing process is used to process the ferroelectric layer 13 to crystallize the ferroelectric material in the ferroelectric layer 13. For example, a rapid thermal annealing process can be used to process the ferroelectric layer 13. During the annealing process, the dangling bonds in the second electrode 12 can absorb oxygen atoms in the ferroelectric layer 13, so that more oxygen vacancies are formed at the second interface Q2 of the ferroelectric layer 13. On the contrary, the first electrode 11 will result in fewer oxygen vacancies at the first interface Q1 of the ferroelectric layer 13. Thus, an oxygen vacancy concentration difference can be formed at the first interface Q1 and the second interface Q2 of the ferroelectric layer 13 to form a uniform built-in electric field in the ferroelectric layer 13.

[0074] In a possible implementation, the first electrode 11 and the second electrode 12 may both include: a first element and a second element, where the first element is a metal element and the second element is a non-metal element. The atomic count ratio of the first element to the second element in the first electrode 11 is different from the atomic count ratio of the first element to the second element in the second electrode 12. In this way, the oxygen vacancy formation energy of the first electrode 11 and the second electrode 12 can be made different. During the manufacturing process, different chemical ratios can be used to manufacture the first electrode 11 and the second electrode 12, so that the atomic count ratio of the first element to the second element in the manufactured first electrode 11 and second electrode 12 is different. Exemplarily, the first element can be elements such as Ti, Ta, Al, etc., and the second element can be elements such as N, P, As, etc. Optionally, the first electrode 11 may include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN, etc., and the second electrode 12 may include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN, etc.

[0075] In one embodiment, the materials of the first electrode 11 and the second electrode 12 may be the same. Continuing to refer to Figure 3 , taking the example that both the first electrode 11 and the second electrode 12 include TiN material, that is, the above-mentioned first element can be Ti and the above-mentioned second element can be N. When manufacturing the first electrode 11 and the second electrode 12, the chemical ratio of the Ti element to the N element can be different. For example, when manufacturing the first electrode 11, the atomic count ratio of the Ti element to the N element can be lower than the target ratio, and when manufacturing the second electrode 12, the atomic count ratio of the Ti element to the N element can be higher than the target ratio. Among them, the target ratio can be the ratio at which the Ti element and the N element exactly react completely. That is to say, there is more N element in the first electrode 11 and more Ti element in the second electrode 12. In this way, there are Ti dangling bonds in the manufactured second electrode 12. During the subsequent process of annealing the ferroelectric layer 13, the Ti dangling bonds will absorb oxygen from the ferroelectric layer 13, resulting in a higher oxygen vacancy content at the second interface Q2 of the ferroelectric layer 13. On the contrary, the more N element in the manufactured first electrode 11 will reduce the oxygen vacancy content at the first interface Q1 of the ferroelectric layer 13, so that the oxygen vacancy concentrations at the first interface Q1 and the second interface Q2 of the ferroelectric layer 13 are different.

[0076] Figure 4 is a schematic diagram of the chemical ratio of the first electrode and the second electrode in the embodiments of the present application. Exemplarily, as Figure 4As shown in (1) therein, the first electrode 11 and the second electrode 12 may both include a TiN material. That is, the above-mentioned first element may be Ti, and the above-mentioned second element may be N. During the manufacturing process, when manufacturing the first electrode 11, the atomic count ratio of Ti element to N element may be lower than the target ratio. When manufacturing the second electrode 12, the atomic count ratio of Ti element to N element may be approximately the target ratio. That is to say, there is more N element in the first electrode 11, and there are basically no extra Ti element and N element in the second electrode 12. In this way, the oxygen vacancy content at the second interface Q2 of the ferroelectric layer 13 obtained by manufacturing can also be relatively high. As Figure 4 As shown in (2) therein, the first electrode 11 and the second electrode 12 may both include a TaN material. That is, the above-mentioned first element may be Ta, and the above-mentioned second element may be N. During the manufacturing process, the atomic count ratio of Ta element to N element when manufacturing the first electrode 11 is lower than the atomic count ratio of Ta element to N element when manufacturing the second electrode 12. That is to say, there is more N element in the first electrode 11, and there is more Ta element in the second electrode 12. In this way, the oxygen vacancy content at the second interface Q2 of the ferroelectric layer 13 obtained by manufacturing can also be relatively high. As Figure 4 As shown in (3) therein, the first electrode 11 and the second electrode 12 may both include a TaAlN material. That is, the above-mentioned first element may be Al, and the above-mentioned second element may be N. During the manufacturing process, the atomic count ratio of Al element to N element when manufacturing the first electrode 11 is lower than the atomic count ratio of Al element to N element when manufacturing the second electrode 12. In this way, the oxygen vacancy content at the second interface Q2 of the ferroelectric layer 13 obtained by manufacturing can also be relatively high.

[0077] In another embodiment, the materials of the first electrode 11 and the second electrode 12 may be different. Exemplarily, the first electrode 11 may include a TiN material, and the second electrode 12 may include a TaN material; or, the first electrode 11 may include a TiAlN material, and the second electrode 12 may include a TiN material. During specific implementation, the materials of the first electrode 11 and the second electrode 12 may be set according to actual needs, and no further examples will be given here.

[0078] The above combination Figure 3 and Figure 4 gives examples of specific implementation methods for manufacturing the first electrode 11 and the second electrode 12 with different chemical ratios. During specific implementation, the chemical ratios of the first electrode 11 and the second electrode 12 may be reasonably set according to the specific materials of the first electrode 11 and the second electrode 12, and no further examples will be given here. In Figure 3 and Figure 4In the illustrated embodiments, an example is given where the oxygen vacancy concentration in the ferroelectric layer 13 at the first interface Q1 is lower than that at the second interface Q2. In a specific implementation, the oxygen vacancy concentration in the ferroelectric layer 13 at the first interface Q1 may also be higher than that at the second interface Q2, as long as the oxygen vacancy concentration in the ferroelectric layer 13 shows a gradient distribution in the first direction F1.

[0079] In the above embodiments, an example is given where both the first electrode and the second electrode include compound materials. In another possible implementation, the first electrode may include a metal material, and the second electrode may include a compound material. Figure 5 This is another schematic diagram of the chemical ratio between the first electrode and the second electrode in the embodiments of the present application. As Figure 5 shown, the first electrode 11 may include: a metal material. For example, the first electrode 11 may include the metal W. Of course, the first electrode 11 may also include other metal materials such as Al and Cu. The second electrode 12 may include: a first element and a second element, where the first element is a metal element and the second element is a non-metal element. Exemplarily, the first element may be Ti, and the second element may be N. Of course, the first element may also include other metal elements such as Ta and Al, and the second element may also include other non-metal materials such as P and As.

[0080] As Figure 5 shown in (1) of, the second electrode 12 may have dangling bonds of the first element. During the manufacturing process, when manufacturing the second electrode 12, the atomic count ratio of the first element to the second element is greater than the target ratio, so that the content of the first element in the manufactured second electrode 12 is relatively high, and the second electrode 12 has dangling bonds of the first element. During the annealing process, the dangling bonds of the first element can absorb oxygen in the ferroelectric layer 13, making the oxygen vacancy concentration in the ferroelectric layer 13 at the second interface Q2 higher than that at the first interface Q1. For example, in the figure, taking the second electrode 12 including TiN material as an example, during the manufacturing process of the second electrode 12, the atomic count ratio of the Ti element to the N element may be higher than the target ratio, so that there are Ti dangling bonds in the manufactured second electrode 12. During the annealing process, the Ti dangling bonds can absorb oxygen in the ferroelectric layer 13, making the oxygen vacancy concentration in the ferroelectric layer 13 at the second interface Q2 relatively high.

[0081] As Figure 5As shown in (2) in [reference], the second electrode 12 may have dangling bonds of the second element. During the manufacturing process, when the second electrode 12 is fabricated, the atomic count ratio of the first element to the second element is less than the target ratio, resulting in a relatively higher content of the second element in the fabricated second electrode 12. The second electrode 12 has dangling bonds of the second element. During the annealing process, the dangling bonds of the second element reduce the oxygen vacancy concentration, causing the oxygen vacancy concentration at the second interface Q2 of the ferroelectric layer 13 to be lower than that at the first interface Q1. Still taking the second electrode 12 including TiN material as an example, during the process of fabricating the second electrode 12, the atomic count ratio of Ti element to N element can be lower than the target ratio, so that N dangling bonds exist in the fabricated second electrode 12. During the annealing process, the N dangling bonds reduce the oxygen vacancy concentration, making the oxygen vacancy concentration at the second interface Q2 of the ferroelectric layer 13 relatively low.

[0082] Figure 5 In [reference], taking the first electrode 11 including a metal material and the second electrode 12 including a compound material as an example, in specific implementation, the first electrode 11 can also be set to include a compound material, and the second electrode 12 can be set to include a metal material.

[0083] Embodiment 2:

[0084] Figure 6a Another structural schematic diagram of the storage unit provided by the embodiment of the present application is shown in Figure 6a As shown. In some other embodiments of the present application, the ferroelectric layer 13 may include at least two stacked ferroelectric thin films 131, and the oxygen vacancy concentrations in adjacent two ferroelectric thin films 131 are different. For example Figure 6a In [reference], taking the ferroelectric layer 13 including four ferroelectric thin films 131 and the oxygen vacancy concentrations of the ferroelectric thin films 131 in the ferroelectric layer 13 showing a pattern of high-low-high-low along the first direction F1 (taking the downward direction along the first direction F1 as an example) as an example, in practical applications, the number of ferroelectric thin films 131 in the ferroelectric layer 13 and the distribution pattern of the oxygen vacancy concentration can be set according to actual needs. In the embodiment of the present application, by setting at least two stacked ferroelectric thin films 131 and having different oxygen vacancy concentrations in adjacent two ferroelectric thin films 131, the oxygen vacancy concentration in the ferroelectric layer 13 can be made to have a gradient distribution (or called a chain distribution), so that a uniform built-in electric field E can be formed in the ferroelectric layer 13. The direction of the built-in electric field E is consistent with the first direction F1, and further induces the polarization direction of the ferroelectric phase to also be arranged along the first direction F1.

[0085] Figure 6b A comparative example of the storage unit in the embodiment of the present application is shown in Figure 6b As shown. When the oxygen vacancy concentration in the ferroelectric layer 13 is uniform, the built-in electric field E formed in the ferroelectric layer 13 is randomly distributed, and the polarization orientation of the ferroelectric phase will also be randomly distributed. In comparison Figure 6aand Figure 6b It can be seen that, compared with the technical solution in which the oxygen vacancy concentration in the ferroelectric layer 13 is uniform, in the embodiments of the present application, by providing at least two stacked ferroelectric thin films 131, and the oxygen vacancy concentrations in two adjacent ferroelectric thin films 131 are different, the oxygen vacancy concentration in the ferroelectric layer 13 can be distributed in a gradient along the first direction F1, so that the built-in electric field E formed by the oxygen vacancy concentration difference is more uniformly distributed along the first direction F1, thereby inducing the polarization directions of the ferroelectric phases to be arranged along the first direction F1.

[0086] In the manufacturing process, the atomic layer deposition (ALD) process can be used to fabricate each ferroelectric thin film 131 in the ferroelectric layer 13. During the deposition of each ferroelectric thin film 131, ferroelectric thin films 131 with different oxygen vacancy concentrations can be formed by controlling the dose of oxygen element (O-dose). Specifically, the dose of oxygen element can be adjusted by controlling parameters such as the residence time, concentration, or flow rate of the oxygen element. Exemplarily, when the ferroelectric layer 13 includes hafnium zirconium oxide (HfxZr1-xO, HZO) material, the oxygen vacancy concentration in the ferroelectric thin film 131 can be controlled by adjusting parameters such as the residence time, concentration, or flow rate of oxygen (O) element, zirconium (Zr) element, and hafnium (Hf) element.

[0087] In the embodiments of the present application, the thickness of the ferroelectric layer 13 can be in the range of 5 nm to 15 nm. For example, the thickness of the ferroelectric layer 13 can be 5 nm, 8 nm, 10 nm, 12 nm, or 15 nm, etc. The thickness of a single ferroelectric thin film 131 can be in the range of 0.5 nm to 2 nm. For example, the thickness of the ferroelectric thin film 131 can be 0.5 nm, 1 nm, 1.5 nm, or 2 nm, etc.

[0088] Figure 7 is a schematic structural diagram of the ferroelectric layer in the embodiments of the present application. Figure 7 In (1) is a schematic diagram of the distribution law of the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer. Figure 7 In (2) is a schematic diagram of the built-in electric field strength at different positions in the ferroelectric layer. In the figure, the ordinate E represents the built-in electric field strength, and the abscissa D represents the distance from the lower surface of the ferroelectric layer (the surface of the ferroelectric layer close to the first electrode). As Figure 7 shown, in a possible implementation, the oxygen vacancy concentrations of the ferroelectric thin films 131 in the ferroelectric layer 13 can be distributed alternately high and low in the first direction F1. For example, in Figure 7 , the oxygen vacancy concentrations of the ferroelectric thin films 131 in the ferroelectric layer 13 can be distributed in the pattern of high, low, high, low, high, low in the first direction F1 (taking upward along the first direction F1 as an example). Figure 8 is another schematic structural diagram of the ferroelectric layer in the embodiments of the present application. Figure 8In (1), it is a schematic diagram of the distribution law of the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer. Figure 8 In (2), it is a schematic diagram of the built-in electric field strength at different positions in the ferroelectric layer. In the figure, the vertical coordinate E represents the built-in electric field strength, and the horizontal coordinate D represents the distance from the lower surface of the ferroelectric layer (the surface of the ferroelectric layer close to the first electrode). As Figure 8 shown, the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can also be distributed in the pattern of low, high, low, high, low, high in the first direction F1 (taking the upward direction along the first direction F1 as an example).

[0089] Figure 9 This is another schematic diagram of the structure of the ferroelectric layer in the embodiment of the present application. Figure 9 In (1), it is a schematic diagram of the distribution law of the oxygen vacancy concentration of each ferroelectric thin film in the ferroelectric layer. Figure 9 In (2), it is a schematic diagram of the built-in electric field strength at different positions in the ferroelectric layer. In the figure, the vertical coordinate E represents the built-in electric field strength, and the horizontal coordinate D represents the distance from the lower surface of the ferroelectric layer (the surface of the ferroelectric layer close to the first electrode). As Figure 9 shown, the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can be distributed in the pattern of first increasing and then decreasing in the first direction F1 (taking the upward direction along the first direction F1 as an example). Or, the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can also be distributed in the pattern of first decreasing and then increasing in the first direction F1.

[0090] The above combination Figures 7 to 9 , introduced several distribution laws of the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13. In practical applications, the number of ferroelectric thin films 131 in the ferroelectric layer 13 and the distribution law of the oxygen vacancy concentration can be set according to actual needs, and no further examples will be given here.

[0091] Based on the same technical concept, the embodiment of the present application also provides a manufacturing method of a storage unit. Figure 10 This is a flowchart of the manufacturing method of the storage unit provided by the embodiment of the present application. As Figure 10 shown, the manufacturing method of the storage unit provided by the embodiment of the present application may include:

[0092] S101. Form a first electrode on a substrate;

[0093] S102. Deposit a ferroelectric layer on the first electrode;

[0094] S103. Form a second electrode on the ferroelectric layer; the first electrode and the second electrode have different oxygen vacancy generation energies;

[0095] S104. Use an annealing process to treat the ferroelectric layer, so that the oxygen element in the ferroelectric layer moves along the first direction, so that the oxygen vacancy concentration in the ferroelectric layer is distributed in a gradient along the first direction, and the first direction is the direction from the first electrode to the second electrode.

[0096] In the embodiments of the present application, by fabricating the first electrode and the second electrode with different oxygen vacancy formation energies, during the subsequent annealing process, the electrode with a higher oxygen vacancy formation energy can absorb the oxygen element in the ferroelectric layer, so that the oxygen element in the ferroelectric layer moves along the first direction, so that the oxygen vacancy concentration in the ferroelectric layer is distributed in a gradient along the first direction, thereby forming a uniform built-in electric field inside the ferroelectric layer, and further improving the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer and the performance of the ferroelectric memory.

[0097] The storage unit in the embodiments of the present application can be a hafnium oxide-based ferroelectric storage unit. In the above step S102, a hafnium oxide material can be used to fabricate the ferroelectric layer. For example, a hafnium zirconium oxide (HfxZr1-xO, HZO) material can be used to fabricate the ferroelectric layer. Of course, in some cases, other ferroelectric materials can also be used to fabricate the ferroelectric layer. In a possible implementation, an atomic layer deposition (ALD) process can be used to fabricate the ferroelectric layer.

[0098] Refer to Figure 3 , in the above steps S101 and S103, different chemical ratios can be used to fabricate the first electrode 11 and the second electrode 12, and dangling bonds capable of absorbing oxygen are formed in one of the electrodes, so that the first electrode 11 and the second electrode 12 have different oxygen vacancy formation energies. Taking the formation of dangling bonds capable of absorbing oxygen in the second electrode 12 as an example, in the above step S104, an annealing process is used to treat the ferroelectric layer 13 so that the ferroelectric material in the ferroelectric layer 13 crystallizes. For example, a rapid thermal annealing process can be used to treat the ferroelectric layer 13. During the annealing process, the dangling bonds in the second electrode 12 can absorb the oxygen atoms in the ferroelectric layer 13, so that more oxygen vacancies are formed at the second interface Q2 of the ferroelectric layer 13. On the contrary, the first electrode 11 will result in fewer oxygen vacancies at the first interface Q1 of the ferroelectric layer 13. Thus, a difference in oxygen vacancy concentration can be formed at the first interface Q1 and the second interface Q2 of the ferroelectric layer 13 to form a uniform built-in electric field in the ferroelectric layer 13.

[0099] In a possible implementation, the first electrode and the second electrode may both include a compound material. Specifically, the first electrode 11 and the second electrode 12 may both include: a first element and a second element, where the first element is a metal element and the second element is a non-metal element. The atomic count ratio of the first element to the second element in the first electrode 11 is different from the atomic count ratio of the first element to the second element in the second electrode 12. In this way, the oxygen vacancy formation energy of the first electrode 11 and the second electrode 12 can be made different. In the above steps S101 and S103, different chemical ratios can be used to fabricate the first electrode 11 and the second electrode 12, so that the atomic count ratio of the first element to the second element in the fabricated first electrode 11 and second electrode 12 is different. Exemplarily, the first element may be elements such as Ti, Ta, Al, etc., and the second element may be elements such as N, P, As, etc. Optionally, the first electrode 11 may include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN, etc., and the second electrode 12 may include one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN, etc.

[0100] In one embodiment, the materials of the first electrode 11 and the second electrode 12 may be the same. For example, the first electrode 11 and the second electrode 12 may both include a TiN material, or the first electrode 11 and the second electrode 12 may both include a TaN material. In another embodiment, the materials of the first electrode 11 and the second electrode 12 may also be different. Exemplarily, the first electrode 11 may include a TiN material and the second electrode 12 may include a TaN material; or the first electrode 11 may include a TiAlN material and the second electrode 12 may include a TiN material. In specific implementation, the materials of the first electrode 11 and the second electrode 12 can be set according to actual needs, and no further examples will be given here.

[0101] In another possible implementation, the first electrode may include a metal material and the second electrode may include a compound material. For example, the first electrode 11 may include metal materials such as metal W, Al, Cu, etc., and the second electrode 12 may include: a first element and a second element, where the first element is a metal element and the second element is a non-metal element. Exemplarily, the first element may be other metal elements such as Ti, Ta, Al, etc., and the second element may also include other non-metal materials such as N, P, As, etc. There may be dangling bonds of the first element in the second electrode; or there may be dangling bonds of the second element in the second electrode. In this way, the oxygen vacancy concentration at the first interface and the second interface of the ferroelectric layer can also be made different.

[0102] Adopting Figure 10 the manufacturing method shown can fabricate the storage unit in the first embodiment above. Figure 10For the specific implementation of the manufacturing method shown, reference may be made to the specific implementation of the storage unit in Embodiment 1 above, and repeated parts will not be elaborated.

[0103] Based on the same inventive concept, an embodiment of the present application also provides a method for manufacturing a storage unit. Figure 11 This is another flowchart of the manufacturing method of the storage unit provided by the embodiment of the present application. As Figure 11 shown, the manufacturing method of the storage unit provided by the embodiment of the present application may include:

[0104] S201. Form a first electrode on a substrate;

[0105] S202. Deposit at least two ferroelectric thin films successively on the first electrode, and make the oxygen vacancy concentration in adjacent two ferroelectric thin films different;

[0106] S203. Form a second electrode on at least two ferroelectric thin films.

[0107] In the embodiment of the present application, by depositing at least two ferroelectric thin films successively on the first electrode and making the oxygen vacancy concentration in adjacent two ferroelectric thin films different, the oxygen vacancy concentration in the ferroelectric layer can be distributed in a gradient manner, so that a uniform built-in electric field can be formed in the ferroelectric layer. The direction of the built-in electric field is consistent with the first direction (the direction from the first electrode to the second electrode), and further induces the polarization direction of the ferroelectric phase to be arranged along the first direction.

[0108] The storage unit in the embodiment of the present application may be a hafnium oxide-based ferroelectric storage unit. In the above step S202, hafnium oxide materials may be used to fabricate each ferroelectric thin film in the ferroelectric layer. For example, hafnium zirconium oxide (HfxZr1-xO, HZO) materials may be used to fabricate the ferroelectric thin film. Of course, in some cases, other ferroelectric materials may also be used to fabricate the ferroelectric thin film.

[0109] Referring to Figure 6a , in the above step S202, an atomic layer deposition (ALD) process may be used to fabricate each ferroelectric thin film 131. During the deposition of each ferroelectric thin film 131, ferroelectric thin films 131 with different oxygen vacancy concentrations can be formed by controlling the dose of oxygen element (O-dose). Specifically, the dose of oxygen element can be adjusted by controlling parameters such as the residence time, concentration, or flow rate of oxygen element. Exemplarily, when the ferroelectric layer 13 includes hafnium zirconium oxide (HfxZr1-xO, HZO) materials, the oxygen vacancy concentration in the ferroelectric thin film 131 can be controlled by adjusting parameters such as the residence time, concentration, or flow rate of oxygen (O) element, zirconium (Zr) element, and hafnium (Hf) element.

[0110] Specifically, in the above step S202, the thickness of the deposited single-layer ferroelectric thin film 131 can be in the range of 0.5 nm to 2 nm. For example, the thickness of the ferroelectric thin film 131 can be 0.5 nm, 1 nm, 1.5 nm, 2 nm, etc. The total thickness of the ferroelectric layer 13 formed by stacking the ferroelectric thin films 131 can be in the range of 5 nm to 15 nm. For example, the total thickness of the ferroelectric layer 13 can be 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, etc.

[0111] In a possible implementation, as Figure 7 and 8 shown, the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can be alternately distributed in a high-low pattern in the first direction F1. Referring to Figure 7 , the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can be regularly distributed in a high-low-high-low-high-low pattern in the first direction F1 (taking the upward direction along the first direction F1 as an example). Or, referring to Figure 8 , the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can also be regularly distributed in a low-high-low-high-low-high pattern in the first direction F1 (taking the upward direction along the first direction F1 as an example). In another possible implementation, referring to Figure 9 , the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can be regularly distributed in a pattern of first increasing and then decreasing in the first direction F1 (taking the upward direction along the first direction F1 as an example). Or, the oxygen vacancy concentration of each ferroelectric thin film 131 in the ferroelectric layer 13 can also be regularly distributed in a pattern of first decreasing and then increasing in the first direction F1. In practical applications, the number of ferroelectric thin films 131 in the ferroelectric layer 13 and the distribution pattern of the oxygen vacancy concentration can be set according to actual needs, and no further examples will be given here.

[0112] Using the Figure 11 shown manufacturing method, the storage unit in the second embodiment above can be manufactured. Figure 11 For the specific implementation of the shown manufacturing method, reference can be made to the specific implementation of the storage unit in the second embodiment above, and the repeated parts will not be elaborated.

[0113] In summary, in the embodiments of the present application, by setting the oxygen vacancy concentration in the ferroelectric layer to be gradient-distributed in the first direction (the first direction is the direction from the first electrode to the second electrode), the texture orientation of the ferroelectric domains can be changed, the uniformity of the polarization orientation of the ferroelectric phase in the ferroelectric layer can be improved, and further the performance of the ferroelectric memory can be improved. For example, the coercive electric field (Ec) of the ferroelectric memory can be reduced, the remanent polarization (Pr) can be increased, and the uniformity of the performance of the small-size ferroelectric memory can be enhanced. Moreover, the technical solution in the embodiments of the present application does not depend on specific electrode materials or the thickness of the ferroelectric thin film, has a wide application range, and low process costs.

[0114] Based on the same inventive concept, the embodiments of the present application further provide a ferroelectric memory. The ferroelectric memory in the embodiments of the present application can be a hafnium oxide-based ferroelectric memory. Of course, the ferroelectric memory in the embodiments of the present application can also be a ferroelectric memory including other ferroelectric materials. The ferroelectric memory in the embodiments of the present application can be various types of memories such as a ferroelectric random access memory (FeRAM or FRAM), a ferroelectric filed effect transistor (FeFET) memory, or a ferroelectric tunneling junction (FTJ) memory.

[0115] The ferroelectric memory provided by the embodiments of the present application may include: a controller and any one of the above-mentioned storage units, and the storage unit is electrically connected to the controller. Since the uniformity of the polarization orientation of the ferroelectric phase in the above-mentioned storage unit is relatively high, the performance of the ferroelectric memory including the above-mentioned storage unit is relatively good.

[0116] Based on the same inventive concept, the embodiments of the present application further provide an electronic device. The electronic device in the embodiments of the present application can be any electronic device with a storage function. For example, the electronic device in the embodiments of the present application can be a mobile phone, a tablet computer, a desktop computer, a smart wearable device, a vehicle-mounted device, a server, a processor, etc.

[0117] The electronic device provided by the embodiments of the present application may include: a circuit board and any one of the above-mentioned ferroelectric memories, and the ferroelectric memory is electrically connected to the circuit board. Since the performance of the above-mentioned ferroelectric memory is relatively high, the performance of the electronic device including the above-mentioned ferroelectric memory is also relatively good.

[0118] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

[0119] 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 equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A storage unit, characterized in that, Comprising: A first electrode, a second electrode, and a ferroelectric layer; The ferroelectric layer is located between the first electrode and the second electrode; The oxygen vacancy concentration in the ferroelectric layer is gradient-distributed in a first direction, and the first direction is the direction from the first electrode pointing to the second electrode.

2. The memory cell according to claim 1, wherein The first electrode and the second electrode have different oxygen vacancy formation energies; The oxygen vacancy concentration at a first interface of the ferroelectric layer is different from that at a second interface; wherein, the first interface is the interface where the ferroelectric layer contacts the first electrode, and the second interface is the interface where the ferroelectric layer contacts the second electrode.

3. The memory cell according to claim 1 or 2, wherein Both the first electrode and the second electrode comprise: a first element and a second element, the first element is a metal element, and the second element is a non-metal element; The atomic count ratio of the first element to the second element in the first electrode is different from that of the first element to the second element in the second electrode.

4. The memory cell according to claim 3, characterized in that, The first electrode comprises: one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN; The second electrode comprises: one or a combination of TiN, TaN, TiAlN, TiSiN, TaAlN, TiAlCN.

5. The memory cell according to claim 1 or 2, characterized in that, The first electrode comprises: a metal material; The second electrode comprises: a first element and a second element, the first element is a metal element, and the second element is a non-metal element; The second electrode has dangling bonds of the first element, or the second electrode has dangling bonds of the second element.

6. The memory cell according to any one of claims 1 to 5, characterized in that, The ferroelectric layer comprises: at least two ferroelectric thin films stacked; The oxygen vacancy concentrations in two adjacent ferroelectric thin films are different.

7. The memory cell according to claim 6, wherein The oxygen vacancy concentrations of the ferroelectric thin films in the ferroelectric layer are distributed in a high-low alternating manner in the first direction.

8. The memory cell according to claim 6, wherein, The oxygen vacancy concentrations of the ferroelectric thin films in the ferroelectric layer are distributed regularly in the first direction, first increasing and then decreasing or first decreasing and then increasing.

9. A ferroelectric memory, characterized in that, Comprising: A controller and a storage unit as described in any one of claims 1 to 8, and the storage unit is electrically connected to the controller.

10. An electronic device, characterized in that, Comprising: A circuit board and a ferroelectric memory as described in claim 9, and the ferroelectric memory is electrically connected to the circuit board.

11. A method for manufacturing a memory cell, characterized in that, Comprising: Forming a first electrode on a substrate; Depositing a ferroelectric layer on the first electrode; Forming a second electrode on the ferroelectric layer; The first electrode and the second electrode have different oxygen vacancy formation energies; Using an annealing process to process the ferroelectric layer to move oxygen elements in the ferroelectric layer in a first direction, so that the oxygen vacancy concentration in the ferroelectric layer is gradient-distributed in the first direction, and the first direction is the direction from the first electrode pointing to the second electrode.

12. A method for manufacturing a memory cell, characterized in that Comprising: Forming a first electrode on the substrate; Sequentially depositing at least two ferroelectric thin films on the first electrode and making the oxygen vacancy concentrations in two adjacent ferroelectric thin films different; Forming a second electrode on the at least two ferroelectric thin films.

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