Magnesium oxide memristor and memory device

Abstract

The invention provides a magnesium oxide memristor and a memory device. The magnesium oxide memristor comprises a substrate, a bottom electrode, a first magnesium oxide layer, a stable layer, a second magnesium oxide layer and a top electrode which are sequentially arranged from bottom to top, and the stabilizing layer is used for stabilizing generation and annihilation of oxygen vacancies in the first magnesium oxide layer and the second magnesium oxide layer. The stable layer is inserted between the magnesium oxide layers, generation and annihilation of oxygen vacancies in the magnesium oxide layers are stabilized by the stable layer, and nucleation and fracture positions of oxygen vacancy conductive wires are pinned by the stable layer, so that resistance fluctuation of the device is reduced; meanwhile, a conductive channel formed by the stable layer and the first magnesium oxide layer and the second magnesium oxide layer on the two sides of the stable layer is no longer a single oxygen vacancy chain, but is of a composite structure, so that the mechanical strength and the thermal stability of the conductive wire are improved, and the durability and the stability of a device are further improved; the problems that an existing magnesium oxide memristor is large in resistance fluctuation and poor in stability are solved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a magnesium oxide memristor and its memory device. Background Technology

[0002] With the rapid development of large models and generative artificial intelligence, AI computing is expanding at an unprecedented pace. Memristors, as a novel type of non-volatile device, can simultaneously realize storage and computation within the same physical unit. They possess characteristics such as high density, low power consumption, and synaptic plasticity, making them a key candidate for next-generation AI hardware.

[0003] The most classic structure of a memristor is the "sandwich" form, consisting of a top electrode, an intermediate dielectric layer, and a bottom electrode arranged sequentially. When a positive bias voltage is applied to the memristor, a conductive filament gradually forms in the intermediate dielectric layer from the end closest to the top electrode until it electrically connects the top and bottom electrodes. At this point, the memristor changes from a non-conductive high-resistance (HRS) state to a low-resistance (LRS) state. If the polarity of the voltage does not change or the voltage is removed, the conductive filament remains and connects the bottom and top electrodes of the memristor, and the memristor maintains its low-resistance state. This is the non-volatility of the memristor. Because the change in the conductive filament determines the change in the memristor's resistance, the stability and uniqueness of the conductive filament become an important criterion for evaluating the performance of a memristor.

[0004] Magnesium oxide (MgO) possesses a wide bandgap (7.3–7.8 eV), a high breakdown field (approximately 12 mV / cm), and controllable ion migration, making it considered an ideal material for the switching layer of memristors. The resistive switching mechanism of MgO memristors primarily relies on the migration and redistribution of oxygen ions / vacancies in the intermediate dielectric layer prepared from MgO under the influence of an electric field, thereby forming or breaking conductive filaments. However, the diverse conduction mechanisms in current MgO memristors lead to significant resistance fluctuations and poor device stability. Summary of the Invention

[0005] The purpose of this invention is to provide a magnesium oxide memristor and a storage device to solve the problems of large resistance fluctuations and poor stability of existing magnesium oxide memristors.

[0006] To address the aforementioned technical problems, the present invention provides a magnesium oxide memristor, comprising a substrate, a bottom electrode, a first magnesium oxide layer, a stabilizing layer, a second magnesium oxide layer, and a top electrode arranged sequentially from bottom to top; the stabilizing layer is used to stabilize the generation and annihilation of oxygen vacancies in the first magnesium oxide layer and the second magnesium oxide layer.

[0007] Optionally, in the magnesium oxide memristor, the stabilizing layer is made of cobalt.

[0008] Optionally, in the magnesium oxide memristor, the thickness of the stabilizing layer is 1.5~3nm.

[0009] Optionally, in the magnesium oxide memristor, the thickness of the first magnesium oxide layer is 10~15 nm.

[0010] Optionally, in the magnesium oxide memristor, the thickness of the second magnesium oxide layer is 2~5 nm.

[0011] Optionally, in the magnesium oxide memristor, the bottom electrode and the top electrode are made of different materials.

[0012] Optionally, in the magnesium oxide memristor, the bottom electrode is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti; and the top electrode is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti.

[0013] To address the aforementioned technical problems, the present invention also provides a storage device, including a magnesium oxide memristor as described in any of the preceding claims.

[0014] The magnesium oxide memristor and memory device provided by this invention include, from bottom to top, a substrate, a bottom electrode, a first magnesium oxide layer, a stabilizing layer, a second magnesium oxide layer, and a top electrode. The stabilizing layer is used to stabilize the generation and annihilation of oxygen vacancies in the first and second magnesium oxide layers. By inserting a stabilizing layer in the middle of the magnesium oxide layers, the generation and annihilation of oxygen vacancies in the magnesium oxide layers are stabilized, and the stabilizing layer "pins" the nucleation and breakage sites of the oxygen vacancy conductive wires, thereby reducing the resistance fluctuation of the device. At the same time, the conductive channel formed by the stabilizing layer and the first and second magnesium oxide layers on both sides is no longer a single oxygen vacancy chain, but a composite structure, thereby improving the mechanical strength and thermal stability of the conductive wires, and thus improving the durability and stability of the device, solving the problems of large resistance fluctuation and poor stability of existing magnesium oxide memristors. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the magnesium oxide memristor provided in this embodiment; Figure 2 A schematic diagram of a conventional magnesium oxide memristor for comparison with the magnesium oxide memristor provided in this embodiment; Figure 3 The IV switching curve of the magnesium oxide memristor provided in this embodiment; Figure 4 The IV switching curve of a conventional magnesium oxide memristor is shown for comparison with the magnesium oxide memristor provided in this embodiment. Figure 5The graph shows the endurance test results of an existing magnesium oxide memristor and the magnesium oxide memristor provided in this embodiment for comparison. Figure 6 This is a graph showing the data retention test results of the magnesium oxide memristor provided in this embodiment; The labels in the attached figures are explained as follows: 100 - Substrate; 110 - Bottom electrode; 120 - First magnesium oxide layer; 130 - Stabilizing layer; 140 - Second magnesium oxide layer; 150 - Top electrode; 200 - Substrate; 210 - Bottom electrode; 220 - Magnesium oxide layer; 230 - Top electrode. Detailed Implementation

[0016] The magnesium oxide memristor and memory device proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non-precise scales, used only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.

[0017] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects in order to describe embodiments of the invention, and are not used to describe a specific order or sequence. It should be understood that such uses of terminology are interchangeable where appropriate. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0018] This embodiment provides a magnesium oxide memristor, such as Figure 1 As shown, the structure includes a substrate 100, a bottom electrode 110, a first magnesium oxide layer 120, a stabilizing layer 130, a second magnesium oxide layer 140, and a top electrode 150 arranged sequentially from bottom to top; the stabilizing layer 130 is used to stabilize the generation and annihilation of oxygen vacancies in the first magnesium oxide layer 120 and the second magnesium oxide layer 140.

[0019] The magnesium oxide memristor provided in this embodiment uses a stabilizing layer inserted in the middle of the magnesium oxide layer, which acts as an effective "oxygen sponge" or "oxygen buffer layer." During the formation and reset of the magnesium oxide memristor, the stabilizing layer stabilizes the generation and annihilation of oxygen vacancies in the magnesium oxide layer and "pins" the nucleation and breakage sites of the oxygen vacancy conductive wires, making them more likely to occur near the interface of the stabilizing layer rather than randomly distributed in the magnesium oxide, thereby reducing the resistance fluctuation of the device. At the same time, the conductive channel formed by the stabilizing layer and the first and second magnesium oxide layers on both sides is no longer a single oxygen vacancy chain, but a composite structure, which improves the mechanical strength and thermal stability of the conductive wires. Under repeated Joule heating and electric field stress, the wires are not easily completely broken or diffused, thereby improving the durability and stability of the device and solving the problems of large resistance fluctuation and poor stability of existing magnesium oxide memristors.

[0020] Specifically, in practical applications, the substrate 100, bottom electrode 110, first magnesium oxide layer 120, stabilizing layer 130, second magnesium oxide layer 140, and top electrode 150 can be bonded and fixed together using methods such as magnetron sputtering, vacuum evaporation, or molecular beam epitaxy. The manufacturing process of the magnesium oxide memristor provided in this embodiment is fully compatible with CMOS processes, reducing manufacturing complexity.

[0021] Furthermore, in this embodiment, the stabilizing layer 130 is made of cobalt (Co). This allows the cobalt layer to stabilize the generation and annihilation of oxygen vacancies in the magnesium oxide layer during the formation and reset of the magnesium oxide memristor, and to "pin" the nucleation and breakage sites of the oxygen vacancy conductive wires, making them more likely to occur in the Co / CoO2 ... x The cobalt layer is located near the interface (cobalt metal or cobalt oxide), rather than randomly distributed in magnesium oxide, thus reducing the resistance fluctuation of the device. At the same time, the conductive channel formed by the cobalt layer and the first and second magnesium oxide layers on both sides is no longer a single oxygen vacancy chain, but a composite structure containing cobalt metal or cobalt oxide. This composite conductive wire has higher mechanical strength and thermal stability, and is not easy to completely break or diffuse under repeated Joule heating and electric field stress, thereby improving the durability and stability of magnesium oxide memristors.

[0022] Furthermore, in this embodiment, the thickness of the stabilizing layer 130 is 1.5~3 nm. The thickness of the first magnesium oxide layer 120 is 10~15 nm; and the thickness of the second magnesium oxide layer 140 is 2~5 nm. By inserting the stabilizing layer 130 into the middle portion of the magnesium oxide layer near the top electrode, the stabilizing effect of the stabilizing layer 130 on the generation and annihilation of oxygen vacancies in the magnesium oxide layer can be better utilized after a voltage is applied to the top electrode.

[0023] Furthermore, in this embodiment, the bottom electrode 110 is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti; the top electrode 150 is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti. Also, in this embodiment, the bottom electrode 110 and the top electrode 150 are made of different materials. For example, the bottom electrode 110 can be made of Pt, and the top electrode 150 can be made of Ti. By using different conductive metal materials for the bottom electrode 110 and the top electrode 150, the formation of conductive filaments in the first magnesium oxide layer 120, the stabilizing layer 130, and the second magnesium oxide layer 140 can be optimized. The asymmetry of the Schottky barrier of different electrodes makes it easier to form a stable and reliable bipolar memristor.

[0024] The following is a comparison of the performance of the magnesium oxide memristor provided in this application with that of existing magnesium oxide memristors using a specific embodiment, to illustrate that the magnesium oxide memristor provided in this application has better device stability.

[0025] In this embodiment, as Figure 1 As shown, the bottom electrode 110 is made of Pt metal, the top electrode 150 is made of Ti metal, the first magnesium oxide layer 120 has a thickness of 10 nm, the stabilizing layer 130 is made of Co with a thickness of 3 nm, and the second magnesium oxide layer 140 has a thickness of 5 nm.

[0026] In contrast, existing magnesium oxide memristor structures, such as Figure 2 As shown, the system includes a substrate 200, a bottom electrode 210, a magnesium oxide layer 220, and a top electrode 230 arranged sequentially from bottom to top. The substrate 200 has the same material, thickness, and dimensions as the substrate 100 of the magnesium oxide memristor provided in this embodiment. The bottom electrode 210 is also made of Pt metal, and its thickness is the same as that of the bottom electrode 110 of the magnesium oxide memristor provided in this embodiment. The top electrode 230 is also made of Ti metal, and its thickness is the same as that of the top electrode 150 of the magnesium oxide memristor provided in this embodiment. The magnesium oxide layer 220 has a thickness of 15 nm, which is the sum of the thicknesses of the first magnesium oxide layer 120 and the second magnesium oxide layer 140 in the magnesium oxide memristor provided in this embodiment.

[0027] Obtain the IV switching curve of the magnesium oxide memristor provided in this embodiment, such as... Figure 3 As shown; and, for comparison, the IV switching curves of an existing magnesium oxide memristor are obtained, as shown. Figure 4 As shown. For Figure 3 and Figure 4 A comparison reveals that the magnesium oxide memristor provided in this embodiment exhibits smaller fluctuations in its switching parameters and better resistance stability.

[0028] In addition, the endurance test results of the magnesium oxide memristor provided in this embodiment and the existing magnesium oxide memristor for comparison are obtained, such as... Figure 5 As shown, where, Figure 5 Figure (a) shows the endurance test results of an existing magnesium oxide memristor for comparison. Figure 5 Figure (b) shows the endurance test results of the magnesium oxide memristor provided in this embodiment. Figure 5 Comparing Figures (a) and (b) reveals that existing magnesium oxide memristors exhibit disordered configurations and are prone to failure after multiple cycles. In contrast, the magnesium oxide memristor provided in this embodiment, by inserting a stabilizing layer, exhibits smaller configuration fluctuations in both the high resistance state (HRS) and the low resistance state (LRS), and maintains device performance without easily failing after multiple cycles.

[0029] Furthermore, a data retention test was performed on the magnesium oxide memristor provided in this embodiment, and the test results are as follows: Figure 6 As shown. From Figure 6 As can be seen, the magnesium oxide memristor provided in this embodiment has good data retention capability and extremely high stability.

[0030] This comparison shows that, compared to existing magnesium oxide memristors, the magnesium oxide memristor provided in this embodiment, by inserting a stabilizing layer into the magnesium oxide layer, acts as an effective "oxygen sponge" or "oxygen buffer layer." During the formation and reset of the magnesium oxide memristor, the stabilizing layer stabilizes the generation and annihilation of oxygen vacancies in the magnesium oxide layer and "pins" the nucleation and breakage locations of the oxygen vacancy conductive wires, making them more likely to occur near the interface of the stabilizing layer rather than randomly distributed throughout the magnesium oxide, thus reducing the device's resistance fluctuations. Simultaneously, the conductive channel formed by the stabilizing layer and the first and second magnesium oxide layers on either side is no longer a single oxygen vacancy chain but a composite structure, thereby improving the mechanical strength and thermal stability of the conductive wires. Under repeated Joule heating and electric field stress, it is less likely to completely break or diffuse, thus improving the device's durability and stability, and solving the problems of large resistance fluctuations and poor stability in existing magnesium oxide memristors.

[0031] This embodiment also provides a storage device, including the magnesium oxide memristor described above.

[0032] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, the different parts between embodiments can also be combined with each other, and this invention does not limit this.

[0033] The magnesium oxide memristor and memory device provided in this embodiment include, from bottom to top, a substrate, a bottom electrode, a first magnesium oxide layer, a stabilizing layer, a second magnesium oxide layer, and a top electrode. The stabilizing layer is used to stabilize the generation and annihilation of oxygen vacancies in the first and second magnesium oxide layers. By inserting a stabilizing layer in the middle of the magnesium oxide layers, the generation and annihilation of oxygen vacancies in the magnesium oxide layers are stabilized, and the stabilizing layer "pins" the nucleation and breakage sites of the oxygen vacancy conductive wires, thereby reducing the resistance fluctuation of the device. At the same time, the conductive channel formed by the stabilizing layer and the first and second magnesium oxide layers on both sides is no longer a single oxygen vacancy chain, but a composite structure, thereby improving the mechanical strength and thermal stability of the conductive wires, and thus improving the durability and stability of the device, solving the problems of large resistance fluctuation and poor stability of existing magnesium oxide memristors.

[0034] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A magnesium oxide memristor, characterized by, It includes a substrate, a bottom electrode, a first magnesium oxide layer, a stabilizing layer, a second magnesium oxide layer, and a top electrode arranged sequentially from bottom to top; the stabilizing layer is used to stabilize the generation and annihilation of oxygen vacancies in the first magnesium oxide layer and the second magnesium oxide layer.

2. The magnesium oxide memristor of claim 1, wherein, The stabilizing layer is made of cobalt.

3. The magnesium oxide memristor of claim 1, wherein, The thickness of the stabilizing layer is 1.5~3nm.

4. The magnesium oxide memristor of claim 1, wherein, The thickness of the first magnesium oxide layer is 10~15 nm.

5. The magnesium oxide memristor of claim 1, wherein, The thickness of the second magnesium oxide layer is 2~5 nm.

6. The magnesium oxide memristor of claim 1, wherein, The bottom electrode and the top electrode are made of different materials.

7. The magnesium oxide memristor of claim 6, wherein, The bottom electrode is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti; the top electrode is made of one or more of Cu, Au, Ag, Pt, Ir, and Ti.

8. A memory device, comprising: Includes the magnesium oxide memristor as described in any one of claims 1 to 7.

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