High-temperature-resistant flexible resistive random access memory device and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant flexible resistive random access memory device and a preparation method thereof, and particularly relates to the field of semiconductor devices. Comprising a metal substrate layer which is made of a high-temperature-resistant flexible metal sheet; the metal lower electrode layer is positioned on the metal substrate layer; the amorphous metal oxide semiconductor layer is positioned on the metal lower electrode layer; and the metal upper electrode layer is positioned on the amorphous metal oxide semiconductor layer. By adopting the technical scheme of the invention, the problem that a traditional rigid resistive random access memory cannot have a high-temperature environment and structural flexibility at the same time is solved, so that the memory has a wide application prospect in some complex and extreme environments.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a high-temperature resistant flexible resistive memory device and a preparation method thereof. Background Art

[0002] Memristor is the fourth basic passive circuit element after resistor, capacitor and inductor, which characterizes the relationship between charge and magnetic flux. The resistance of a memristor can switch between at least two different resistance states and maintain this change after the electric field excitation is removed, which makes it applicable as a new type of resistive memory device. Compared with traditional non-volatile memory devices, resistive memory has shown unique advantages in storage density, erase and write speed, power consumption, etc., and is considered to be one of the important candidates for the next generation of universal memory.

[0003] With the exploration of science and technology, resistive memory devices are still required to have high resistive performance and high reliability in some harsh environments. The current research is mainly aimed at the design and development of flexible resistive memory, but due to the limitation of substrate materials, it is difficult to maintain good resistive performance and excellent reliability at high temperatures. Therefore, the development of a resistive memory device that is both resistant to high temperatures and bendable will make resistive memory have broad application prospects in some complex and extreme environments. Summary of the invention

[0004] The present invention aims to provide a high temperature resistant flexible resistive memory device and a preparation method thereof, which solves the problem that traditional rigid memory devices cannot meet the requirements of both high temperature and structural flexibility.

[0005] In order to achieve the above object, the present invention provides a technical solution as follows: a high temperature resistant flexible resistive memory device, comprising:

[0006] A metal substrate layer, wherein the substrate layer is made of a high temperature resistant flexible metal sheet;

[0007] A lower electrode layer, wherein the lower electrode layer is located on the metal substrate layer;

[0008] an amorphous metal oxide semiconductor layer, wherein the amorphous metal oxide semiconductor layer is located on the lower electrode layer;

[0009] An upper electrode layer, wherein the upper electrode layer is located on the amorphous metal oxide semiconductor layer;

[0010] Furthermore, the metal foil substrate is a commercial copper foil with a thickness of 10-100 μm. The above material can be used as a substrate to withstand higher temperatures in photoelectric tests.

[0011] Furthermore, the metal layer is an Al film or a Cu film with a thickness of 100-200 nm, which can achieve high surface flatness requirements.

[0012] Furthermore, the amorphous metal oxide semiconductor material is amorphous TaO x Thin film or Ga 2 O 3 Thin film, the thickness of which is 10-50nm.

[0013] Furthermore, the upper electrode layer is made of inert metal Pt or Au, and has a thickness of 50-100 nm.

[0014] The present invention also provides another embodiment, a method for preparing a high temperature resistant flexible resistive memory device, comprising the following steps:

[0015] Step 1: clean the substrate to ensure that the surface is flat and free of impurities;

[0016] Step 2, depositing upward on the surface of the metal substrate by magnetron sputtering to finally obtain a thin film layer, which is the lower electrode layer;

[0017] Step 3, continuing to deposit upwards again by magnetron sputtering to finally obtain an amorphous metal oxide semiconductor layer;

[0018] Step 4: Continue to deposit upwards using a thermal evaporation method to eventually obtain a thin film layer, which is the upper electrode layer.

[0019] The specific conditions of magnetron sputtering in step 2 are: the sputtering gas is high-purity argon, the sputtering power is 120W, and the back vacuum is less than 5.0×10 -4 Pa, the growth pressure is 2 Pa, the growth temperature is 500 ° C, and the sputtering target is Cu ceramic target or Al ceramic target.

[0020] The specific conditions of magnetron sputtering in step 3 are as follows: the sputtering gas is argon: oxygen = 19:1, the sputtering power is 80W, and the back vacuum is less than 2.0×10 -4 Pa, the growth pressure is 2Pa, the growth temperature is room temperature, and the sputtering target is TaO x Ceramic target or Ga 2 O 3 Ceramic target.

[0021] The specific conditions for thermal evaporation in step 4 are: the back vacuum is less than 5.0×10 -4 Pa, the evaporation material is 99.99% Pt wire. The upper electrode is distributed in a circular array, and its diameter is 10-100um.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Compared with the resistive memory device constructed with traditional flexible materials, the device constructed by the present invention has better thermal stability and flexibility, and exhibits better resistive performance and reliability under high temperature and bending conditions.

[0024] 2. The resistive memory device adopts magnetron sputtering technology to prepare the resistive layer. The preparation process is relatively simple and the cost is low, which reduces the production cost and is conducive to the mass production and wide application of resistive memory devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of the current-voltage relationship of the memory device of the present invention when the device is turned on and off at room temperature and without bending.

[0026] Figure 2 This is a schematic diagram of the current-voltage relationship when the memory device of the present invention is turned on and off at room temperature with a curvature radius of 0.8 cm.

[0027] Figure 3 This is a statistical diagram of the high resistance state and the low resistance state of the memory device of the present invention at room temperature and different curvature radii.

[0028] Figure 4 This is a schematic diagram of the current-voltage relationship when the memory device of the present invention is turned on and off at 200° C. and a curvature radius of 0.8 cm.

[0029] Figure 5 It is a statistical data diagram of the high resistance state and the low resistance state of the memory device of the present invention under the condition that the curvature radius is 0.8 cm at different temperatures. DETAILED DESCRIPTION

[0030] The resistive memory device of this embodiment is characterized by selecting a metal substrate layer, a lower electrode layer, and an amorphous metal oxide semiconductor layer of appropriate thickness, which has good bending performance and can withstand higher ambient temperatures. Therefore, it is possible to construct a high-temperature resistant flexible resistive memory device.

[0031] The following will disclose multiple embodiments of the present invention with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some existing conventional structures and elements will be depicted in a simple schematic manner in the drawings, and in all drawings, the same reference numerals will be used to represent the same or similar elements. In the absence of conflict, the features of different embodiments can be applied interchangeably.

[0032] Embodiment 1:

[0033] Stainless steel was selected as the substrate, which was cleaned by washing with acetone, alcohol and deionized water, and then dried with nitrogen gas;

[0034] Using magnetron sputtering, a 150nm thick Al film and a 10nm thick TaO film were deposited on the substrate in sequence. x Al thin film as the lower electrode layer, TaO x The thin film is an amorphous metal oxide semiconductor layer.

[0035] Specifically, the specific preparation conditions of Al film are: back vacuum: less than 5.0×10 -4 Pa; sputtering gas is high-purity argon; growth pressure: 2Pa; sputtering target: Al target; sputtering power: 120W; substrate temperature: 500℃.

[0036] Specifically, TaO x The specific preparation conditions of the film are: back vacuum: less than 2.0×10 -4 Pa; sputtering gas: argon: oxygen = 19:1; growth pressure: 2Pa; sputtering target: TaO x Target; sputtering power: 80W; substrate temperature: room temperature.

[0037] Finally, thermal evaporation is used to continue deposition upwards, and a Pt metal film with a thickness of about 75 nm is deposited as an upper electrode layer, and the shape of the film is a circular array with a diameter of 30 um.

[0038] Embodiment 2:

[0039] A 20um copper foil was selected as the substrate, which was cleaned with acetone, alcohol and deionized water, and then dried with nitrogen gas for cleaning.

[0040] Using magnetron sputtering, a 120nm thick Cu film and a 50nm thick Ga film were deposited on the substrate in sequence. 2 O 3 Al thin film as the lower electrode layer, Ga 2 O 3 The thin film is an amorphous metal oxide semiconductor layer.

[0041] Specifically, the specific preparation conditions of Al film are: back vacuum: less than 5.0×10 -4 Pa; sputtering gas is high-purity argon; growth pressure: 2Pa; sputtering target: Al target; sputtering power: 120W; substrate temperature: 500℃.

[0042] Specifically, 2 O 3 The specific preparation conditions of the film are: back vacuum: less than 2.0×10-4 Pa; sputtering gas is high-purity argon; growth pressure: 2Pa; sputtering target: Ga 2 O 3 Target; sputtering power: 80W; substrate temperature: room temperature.

[0043] Finally, a Ta metal film with a thickness of about 60 nm is deposited as an upper electrode layer by a thermal evaporation method, and the shape of the film is a circular array with a diameter of 50 um.

[0044] The following experiments were performed using the prepared device 1:

[0045] In this example, Figure 1 As shown, under the positive voltage scan, it can be observed that the device is turned on at 1.0V and converted from a high-resistance state to a low-resistance state. Under the negative voltage scan, the device is turned off at -0.5V and converted from a low-resistance state to a high-resistance state, indicating that the device can normally realize the memristive behavior.

[0046] Bend the device as Figure 2 As shown, the radius R of the sector after bending is 0.8 cm. It can be observed that the device is turned on at 1.0 V and switches from a high resistance state to a low resistance state. Under a negative voltage scan, the device is turned off at -0.4 V and switches from a low resistance state to a high resistance state, indicating that the device has good flexibility and can normally realize resistive switching behavior.

[0047] like Figure 4 As shown, at different curvature radii, the resistive switching behavior of the device was tested, and the resistance values ​​of the high resistance state and the low resistance state were counted. It was found that the resistance values ​​of the high and low resistance states of the device at different curvature radii were almost consistent, indicating that the device has good flexibility.

[0048] Bend the device as Figure 3 As shown, the radius R of the fan after bending is 0.8cm, and the device is placed in a high temperature environment of 200°C for heating. Under the forward voltage scan, it can be observed that the device is turned on at 1.0V and switches from a high resistance state to a low resistance state. Under the negative voltage scan, the device is turned off at -0.6V and switches from a low resistance state to a high resistance state, indicating that the device has good flexibility and can normally realize resistive switching behavior in a high temperature environment, and has good thermal stability.

[0049] Bend the device as Figure 5 As shown in the figure, the radius R of the fan after bending is 0.8 cm. Under different temperature conditions, the device is tested for resistance switching behavior, and the resistance values ​​of the high resistance state and the low resistance state are counted. It is found that the resistance values ​​of the high and low resistance states of the device are almost consistent under certain bending and different temperatures, indicating that the device has good flexibility and good thermal stability. This proves that the device is a high temperature resistant flexible device.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A high temperature resistant flexible resistive memory device, characterized in that: It comprises a high temperature resistant flexible metal substrate layer, on which are arranged, from bottom to top, a lower electrode layer, an amorphous metal oxide semiconductor layer and an upper electrode layer.

2. The high temperature resistant flexible resistive memory device according to claim 1, characterized in that: The high temperature resistant flexible metal substrate material is commercial stainless steel or copper foil, and its thickness is 10-100 μm.

3. The high temperature resistant flexible resistive memory device according to claim 1, characterized in that: The lower electrode layer is made of metal Al or Cu, and has a thickness of 100-200 nm.

4. The high temperature resistant flexible resistive memory device according to claim 1, characterized in that: The amorphous metal oxide semiconductor layer is amorphous TaO x Thin film or Ga2O3 thin film, the thickness of which is 10-50nm.

5. The high temperature resistant flexible resistive memory device according to claim 1, characterized in that: The upper electrode layer is made of inert metal Pt or Au, and has a thickness of 50-100 nm.

6. A method for preparing a high temperature resistant flexible resistive memory device, characterized in that: The steps include: Step 1: clean the substrate to ensure that the surface is flat and free of impurities; Step 2, depositing upward on the substrate surface by magnetron sputtering to finally obtain a thin film layer, which is the lower electrode layer; Step 3, continuing to deposit upwards again by magnetron sputtering to finally obtain an amorphous metal oxide semiconductor layer; Step 4: Continue to deposit upwards using a thermal evaporation method to eventually obtain a thin film layer, which is the upper electrode layer.

7. The method for preparing a high temperature resistant flexible resistive memory device according to claim 6, characterized in that: The specific conditions of magnetron sputtering in step 2 are: the sputtering gas is high-purity argon, the sputtering power is 120W, and the back vacuum is less than 5.0×10 -4 Pa, the growth pressure is 2Pa, and the growth temperature is 500℃.

8. The method for preparing a high temperature resistant flexible resistive memory device according to claim 6, characterized in that: The specific conditions of magnetron sputtering in step 3 are as follows: the sputtering gas is argon: oxygen = 19:1, the sputtering power is 80W, and the back vacuum is less than 2.0×10 -4 Pa, the growth pressure is 2Pa, and the growth temperature is room temperature.

9. The method for preparing a high temperature resistant flexible resistive memory device according to claim 6, characterized in that: The sputtering target in step 2 is a Cu metal target or an Al metal target, and the sputtering target in step 3 is a Ta2O5 ceramic target or a Ga2O3 ceramic target.

10. The method for preparing a high temperature resistant flexible resistive memory device according to claim 6, characterized in that: The thin film layer in step 4 is a metal Pt or Au thin film, which is distributed in a circular array and has a diameter of 10-100 μm.

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