A cbram device based on ti-cu alloy electrode and a preparation method thereof

Abstract

The present invention provides a CBRAM device based on a Ti-Cu alloy electrode and a method for preparing the same. The CBRAM device based on a Ti-Cu alloy electrode comprises a substrate, a first electrode, a resistive switching layer, and a second electrode. The first and second electrodes are made of either an active electrode material or an inert electrode material. When the first electrode is made of an active electrode material, the second electrode is made of an inert electrode material. When the first electrode is made of an inert electrode material, the second electrode is made of an active electrode material. The active electrode material is a Ti-Cu alloy. Using a Ti-Cu alloy electrode instead of a Cu electrode limits the number of Cu atoms injected from the electrode to form conductive filaments, significantly improving the durability of the CBRAM device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microelectronic integrated circuits, and in particular to a CBRAM device based on a Ti-Cu alloy electrode and a preparation method thereof. BACKGROUND

[0002] With the rapid development of information technology, the demand for memory is increasing. RRAM, as a new type of non-volatile memory, has attracted much attention due to its fast read-write speed, high density, low power consumption and other advantages. CBRAM (Conductive Bridging Random Access Memory) is a kind of RRAM, which realizes data storage by forming a conductive bridge between electrodes. CBRAM generally has a sandwich structure, one end of which usually adopts an active electrode such as Cu or Ag, the other end of which usually adopts an inert electrode such as Pt or TiN, and the middle switch layer is a solid electrolyte, which usually adopts an oxide or a sulfide. Under the action of an electric field, the formation and rupture of the conductive bridge cause the device to exhibit resistance state switching.

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

[0004] Based on the shortcomings of the existing CBRAM devices based on pure metal electrodes, it is necessary to improve them. SUMMARY

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

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

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

[0008] a substrate;

[0009] a first electrode on the surface of the substrate;

[0010] a resistance change layer on the surface of the first electrode away from the substrate;

[0011] a second electrode arrayed on the surface of the resistance change layer away from the substrate;

[0012] The material of the first electrode and the second electrode is active electrode material or inert electrode material, when the material of the first electrode is active electrode material, the material of the second electrode is inert electrode material; when the material of the first electrode is inert electrode material, the material of the second electrode is active electrode material.

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

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

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

[0016] The material of the resistance change layer comprises any one of hafnium oxide, silicon oxide, zirconium oxide, germanium telluride and germanium selenide.

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

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

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

[0020] The thickness of the resistance change layer is 1-800 nm.

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

[0022] In a second aspect, the application further provides a preparation method of the CBRAM device based on the Ti-Cu alloy electrode.

[0023] The first electrode is prepared on the surface of the substrate.

[0024] The resistance change layer is prepared on the surface of the first electrode.

[0025] The second electrode is prepared on the surface of the resistance change layer.

[0026] Preferably, the preparation method of the Ti-Cu alloy comprises: taking a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the pressure in a sputtering cavity is 0.2-0.8 Pa, the sputtering power of Cu is 1-40 W, the sputtering time of Cu is 180-6000 s, the sputtering power of Ti is 1-40 W, and the sputtering time of Ti is 180-6000 s.

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

[0028] The CBRAM device based on the Ti-Cu alloy electrode and the preparation method thereof have the following advantages over the prior art

[0029] Advantages:

[0030] The CBRAM device based on the Ti-Cu alloy electrode comprises a substrate, a first electrode, a resistive switching layer and a second electrode. The material of the first electrode and the second electrode is active electrode material or inert electrode material. When the material of the first electrode is active electrode material, the material of the second electrode is inert electrode material. When the material of the first electrode is inert electrode material, the material of the second electrode is active electrode material. The active electrode material is Ti-Cu alloy. The use of the Ti-Cu alloy electrode instead of the Cu electrode limits the number of Cu atoms injected from the electrode to form conductive filaments, and greatly improves the durability of the CBRAM device. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0032] Figure 1 FIG. 1 is a structural schematic diagram of the CBRAM device based on the Ti-Cu alloy electrode;

[0033] Figure 2 FIG. 2 is an I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in Example 1;

[0034] Figure 3 Resistance state distribution plot for the CBRAM device based on Ti-Cu electrode prepared in Example 2;

[0035] Figure 4 I-V curve plot for the CBRAM device based on Ti-Cu electrode prepared in Example 3;

[0036] Figure 5 Resistance state distribution plot for the CBRAM device based on Ti-Cu electrode prepared in Example 3;

[0037] Figure 6 I-V curve plot for the CBRAM device based on Ti-Cu electrode prepared in Example 3;

[0038] Figure 7 Resistance state distribution plot for the CBRAM device based on Ti-Cu electrode prepared in Example 3;

[0039] Figure 8 I-V curve plot for the CBRAM device based on Cu alloy electrode prepared in Comparative Example 1;

[0040] Figure 9 Resistance state distribution plot for the CBRAM device based on Cu alloy electrode prepared in Comparative Example 1;

[0041] Figure 10 I-V curve plot for the OxRAM device based on Ti electrode prepared in Comparative Example 2;

[0042] Figure 11 Resistance state distribution plot for the OxRAM device based on Ti electrode prepared in Comparative Example 2.

[0043] Figure 12 XPS analysis plot of Cu element in Ti-Cu alloy electrode prepared in Example 2;

[0044] Figure 13 XPS analysis plot of Ti element in Ti-Cu alloy electrode prepared in Example 2;

[0045] Figure 14 XPS analysis plot of Cu element in Ti-Cu alloy electrode prepared in Example 3;

[0046] Figure 15 XPS analysis plot of Ti element in Ti-Cu alloy electrode prepared in Example 3. DETAILED DESCRIPTION

[0047] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be understood that the directions or positions indicated by “upper” and the like are based on the directions or positions shown in the accompanying drawings, or are the directions or positions in which the product of the invention is usually placed when in use, or are the directions or positions commonly understood by those skilled in the art. These directions or positions are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0049] The order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of this application, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be understood as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0050] The embodiment of the present application provides a CBRAM device based on Ti-Cu alloy electrodes, such as Figure 1 Shown, including:

[0051] Substrate 1;

[0052] A first electrode 2, which is located on the surface of the substrate 1;

[0053] The resistive switching layer 3 is located on the surface of the first electrode 2 away from the substrate 1;

[0054] The second electrodes 4 are arranged in an array on the surface of the resistive layer 3 away from the substrate 1;

[0055] The material of the first electrode 2 and the second electrode 4 is an active electrode material or an inert electrode material, when the material of the first electrode 2 is the active electrode material, the material of the second electrode 4 is the inert electrode material; when the material of the first electrode 2 is the inert electrode material, the material of the second electrode 4 is the active electrode material.

[0056] The active electrode material is a Ti-Cu alloy.

[0057] The CBRAM device based on the Ti-Cu alloy electrode of the application comprises a substrate 1, a first electrode 2, a resistive switching layer 3, and a second electrode 4; wherein the substrate 1, the first electrode 2, and the resistive switching layer 3 are sequentially stacked; the second electrode 4 is arranged in an array on the surface of the resistive switching layer 3 away from the substrate 1; the positions of the first electrode 2 and the second electrode 4 can be replaced with each other, the material of the first electrode 2 and the second electrode 4 is an active electrode material or an inert electrode material, when the material of the first electrode 2 is the active electrode material, the material of the second electrode 4 is the inert electrode material; when the material of the first electrode 2 is the inert electrode material, the material of the second electrode 4 is the active electrode material; that is, when the first electrode 2 is the active electrode, the second electrode 4 is the inert electrode, and when the first electrode 2 is the inert electrode, the second electrode 4 is the active electrode; specifically, the material of the active electrode is a Ti-Cu alloy, the Cu electrode is replaced with the Ti-Cu alloy electrode, the number of Cu atoms injected from the electrode to form the conductive filament is limited, and the durability of the CBRAM device can be greatly improved.

[0058] In some embodiments, the mass fraction of Cu in the Ti-Cu alloy is 22-99%, and the rest is Ti (i.e., the mass fraction of Ti is 78-1%).

[0059] In some embodiments, the inert electrode material includes at least one of Ti, Pt, W, and TiN (titanium nitride).

[0060] In some embodiments, the material of the resistive switching layer 3 includes any one of hafnium oxide, silicon oxide, and zirconium oxide.

[0061] In some embodiments, the substrate 1 includes any one of a Si / SiO2 / Ti substrate, a Si substrate, a SiO2 substrate, a c-surface sapphire substrate, a magnesium oxide substrate, a gallium oxide substrate, a gallium nitride substrate, an NSTO substrate, a quartz glass substrate, an r-surface sapphire substrate, and an a-surface sapphire substrate.

[0062] In some embodiments, the shape of the second electrode 4 is a rectangle or a circle, the side length of the rectangle is 10 nm-10 mm, and the diameter of the circle is 10 nm-10 mm.

[0063] In some embodiments, the thickness of the first electrode 2 is 10-900 nm.

[0064] In some embodiments, the thickness of the resistance change layer 3 is 1-800 nm.

[0065] In some embodiments, the thickness of the second electrode 4 is 10-900 nm.

[0066] In some embodiments, the substrate 1 is a Si / SiO2 / Ti substrate, i.e., the substrate 1 comprises a Si layer, a SiO2 layer and a Ti layer which are sequentially stacked, and the first electrode 2 is located on the surface of the Ti layer, wherein the thickness of the Si is 500-600 μm, the thickness of the SiO2 is 500-600 nm, and the thickness of the Ti is 50-100 nm.

[0067] Based on the same inventive concept, the application further provides a preparation method of the CBRAM device based on the Ti-Cu alloy electrode as described above, comprising the following steps:

[0068] S1, preparing the first electrode on the surface of the substrate;

[0069] S2, preparing the resistance change layer on the surface of the first electrode;

[0070] S3, preparing the arrayed second electrode on the surface of the resistance change layer.

[0071] Specifically, the growth method of the first electrode, the resistance change layer and the second electrode can be chemical vapor deposition, physical vapor deposition or the like; the physical vapor deposition can be magnetron sputtering or the like.

[0072] In some embodiments, the first electrode is prepared by magnetron sputtering, wherein the process parameters controlled during the magnetron sputtering are as follows: the pressure in the sputtering cavity is 0.2-0.8 Pa, the sputtering power is 1-40 W, and the sputtering time is 180-6000 s.

[0073] In some embodiments, the resistance change layer is prepared on the surface of the first electrode by magnetron sputtering, wherein the process parameters controlled during the magnetron sputtering are as follows: the pressure in the sputtering cavity is 0.2-0.8 Pa, the sputtering power is 1-60 W, and the sputtering time is 100-7000 s.

[0074] In some embodiments, the preparation method of the Ti-Cu alloy comprises: taking a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by magnetron sputtering, wherein the process parameters controlled during the magnetron sputtering are as follows: the pressure in the sputtering cavity is 0.2-0.8 Pa, the sputtering power of the Cu is 1-40 W, the sputtering time of the Cu is 180-6000 s, the sputtering power of the Ti is 1-40 W, and the sputtering time of the Ti is 180-6000 s.

[0075] In some embodiments, the second electrode material is an active electrode material, the active electrode material is a Ti-Cu alloy, and a preparation method of the Ti-Cu alloy comprises: taking a Cu target and a Ti target as raw materials, using a mask and preparing an array of the second electrode on the surface of the resistance change layer by a magnetron sputtering method, wherein process parameters controlled during the magnetron sputtering are as follows: the pressure in a sputtering cavity is 0.2-0.8 Pa, the sputtering power of Cu is 1-40 W, the sputtering time of Cu is 180-6000 s, the sputtering power of Ti is 1-40 W, and the sputtering time of Ti is 180-6000 s.

[0076] In some embodiments, the method further comprises cleaning the substrate before the first electrode is prepared on the surface of the substrate, and the cleaning method comprises the following steps: first, placing the substrate in a beaker, pouring acetone into the beaker for cleaning, sealing the beaker with a plastic wrap because the acetone is a volatile solution, and then ultrasonic cleaning for 30-35 min, which is mainly to remove organic impurities; after cleaning, taking out the substrate with tweezers, placing the substrate in another beaker, pouring anhydrous ethanol into the beaker, and ultrasonic cleaning for 30-35 min, which is mainly to remove acetone and other surface contaminants; finally, placing the substrate in a beaker containing deionized water, and ultrasonic cleaning for 30-35 min, and then blowing dry for standby use.

[0077] In some embodiments, the resistance change layer is prepared on the surface of the first electrode by a magnetron sputtering method, and the method comprises the following steps: first, installing a target material (such as a hafnium oxide target) on a direct current sputtering target holder of a magnetron sputtering device, starting a molecular pump and a mechanical pump to pump air so that the air pressure in a sputtering vacuum chamber is lower than 2×10 -4 Pa, and then starting argon and a secondary circulation cooling water switch. Then, sticking an insulating tape to one side edge of the substrate on which the first electrode is prepared, fixing the substrate on a sample holder in the magnetron sputtering device, placing the substrate in a small cavity, and waiting until the air pressure in the small cavity reaches 5×10 -3 Pa, and then conveying the substrate into a vacuum sputtering chamber; at room temperature 25℃, introducing argon as an inert gas into the vacuum chamber of the magnetron sputtering device, controlling the flow rate of the argon to be 40-60 sccm, starting an alternating current sputtering power supply, controlling the system pressure in the vacuum chamber to be 0.2-0.4 Pa at room temperature, controlling the sputtering power of the target material to be 1-60 W, and controlling the sputtering time to be 100-7000 s, and after the deposition is completed, stopping the alternating current sputtering power supply, and thus the resistance change layer is obtained.

[0078] In some embodiments, the second electrode material is an active electrode material, and the active electrode material is a Ti-Cu alloy. The Ti-Cu alloy is prepared by using a Cu target and a Ti target as raw materials, using a mask and a common magnetron sputtering method to prepare an array of second electrodes on the surface of the resistive switching layer. By adjusting the sputtering temperature, sputtering pressure, sputtering power, and sputtering time, a high-performance CBRAM device can be prepared. The specific operation is as follows: cover one side of the resistive switching layer with a mask and fix it with insulating glue. The mask has square and circular apertures, with a side length of 10 nm to 10 mm for the square apertures and a diameter of 10 nm to 10 mm for the circular apertures. Therefore, the size and shape of the prepared Ti-Cu electrode are consistent with those of the mask. Install the Ti target and the Cu target on a magnetron sputtering device. At room temperature of 25°C, introduce argon gas as an inert gas into the vacuum chamber of the magnetron sputtering device. The flow rate of the argon gas is controlled at 50-60 sccm, the pressure in the sputtering cavity is 0.2-0.8 Pa, the RF power supply switch is turned on, the sputtering power of Cu is 1-40 W, the sputtering time of Cu is 180-6000 s, the sputtering power of Ti is 1-40 W, the sputtering time of Ti is 180-6000 s, and the deposition is completed. Then, the direct current sputtering power is turned off, and the second electrode is obtained.

[0079] The application further illustrates the Ti-Cu alloy electrode-based CBRAM device and the preparation method thereof with specific examples. This part further illustrates the content of the application in combination with specific examples, but should not be understood as a limitation of the application. Unless otherwise specified, the technical means used in the examples are conventional means known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the application are conventional reagents, methods, and equipment in the art.

[0080] Example 1

[0081] The application provides a Ti-Cu alloy electrode-based CBRAM device, which comprises:

[0082] a substrate;

[0083] a first electrode on the surface of the substrate;

[0084] a resistive switching layer on the surface of the first electrode away from the substrate;

[0085] a second electrode arrayed on the surface of the resistive switching layer away from the substrate;

[0086] The material of the first electrode is an inert electrode material Pt.

[0087] The material of the second electrode is an active electrode material, and the active electrode material is a Ti-Cu alloy. The mass fraction of Ti in the Ti-Cu alloy is 25%, and the remaining part is Cu (i.e., the mass fraction of Cu is 75%).

[0088] The material of the resistance change layer is hafnium oxide;

[0089] The substrate comprises a Si / SiO2 / Ti substrate, the substrate comprises a Si layer, a SiO2 layer and a Ti layer which are sequentially stacked, and the first electrode is located on the surface of the Ti layer, wherein the thickness of the Si layer is 500 μm, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm;

[0090] The thickness of the first electrode is 200 nm;

[0091] The thickness of the resistance change layer is 100 nm;

[0092] The thickness of the second electrode is 250 nm;

[0093] The shape of the second electrode is a square, and the side length of the square is 500 μm.

[0094] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in the above embodiment 1 comprises the following steps:

[0095] S1, sequentially clean the Si / SiO2 / Ti substrate with acetone for 30 min, with anhydrous ethanol for 20 min, and with deionized water for 10 min, and then dry the substrate for standby;

[0096] S2, deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by a magnetron sputtering method to obtain a first electrode, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50 sccm, the pressure of the sputtering chamber is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0097] S3, use a hafnium oxide target as raw material to prepare a resistance change layer on the surface of the first electrode by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 40 sccm, the pressure of the sputtering chamber is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0098] S4, use a Cu target and a Ti target as raw materials to prepare an array of second electrodes on the surface of the resistance change layer by a mask and a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50 sccm, the pressure of the sputtering chamber is 0.35 Pa, the sputtering power of Cu is 10 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 3 W, and the sputtering time of Ti is 1800 s.

[0099] Embodiment 2

[0100] The embodiment of the application provides a CBRAM device based on a Ti-Cu alloy electrode, comprising:

[0101] a substrate;

[0102] a first electrode located on a surface of the substrate;

[0103] a resistive switching layer located on a surface of the first electrode away from the substrate;

[0104] a second electrode arranged in an array on a surface of the resistive switching layer away from the substrate;

[0105] The material of the first electrode is inert electrode material Pt.

[0106] The material of the second electrode is active electrode material, the active electrode material is a Ti-Cu alloy, the mass fraction of Ti in the Ti-Cu alloy is 1%, and the rest is Cu (i.e., the mass fraction of Cu is 99%);

[0107] The material of the resistive switching layer is hafnium oxide.

[0108] The substrate comprises a Si / SiO2 / Ti substrate, the substrate comprises a Si layer, a SiO2 layer and a Ti layer which are sequentially stacked, and the first electrode is located on a surface of the Ti layer, wherein the thickness of the Si layer is 500 mu m, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm.

[0109] The thickness of the first electrode is 200 nm.

[0110] The thickness of the resistive switching layer is 100 nm.

[0111] The thickness of the second electrode is 250 nm.

[0112] The shape of the second electrode is a square, and the side length of the square is 500 mu m.

[0113] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in the above embodiment 2 comprises the following steps:

[0114] S1, sequentially ultrasonic cleaning the Si / SiO2 / Ti substrate with acetone for 30 minutes, ultrasonic cleaning with anhydrous ethanol for 20 minutes, and ultrasonic cleaning with deionized water for 10 minutes, and then blowing dry for standby after the ultrasonic cleaning is completed;

[0115] S2, depositing a Pt layer on the cleaned Si / SiO2 / Ti substrate by using a magnetron sputtering method to obtain the first electrode, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25 DEG C, the flow rate of argon is 50 sccm, the pressure of the sputtering cavity is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0116] S3, taking a hafnium oxide target as raw material, a resistive switching layer is prepared on the surface of the first electrode by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25 DEG C, the flow rate of argon is 40 sccm, the pressure of the sputtering cavity is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0117] S4, taking a Cu target and a Ti target as raw material, a second electrode arranged in an array is prepared on the surface of the resistive switching layer by a mask and a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25 DEG C, the flow rate of argon is 50 sccm, the pressure of the sputtering cavity is 0.35 Pa, the sputtering power of Cu is 40 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 1 W, and the sputtering time of Ti is 1800 s.

[0118] Embodiment 3

[0119] The embodiment of the present application provides a CBRAM device based on a Ti-Cu alloy electrode, comprising:

[0120] a substrate;

[0121] a first electrode located on the surface of the substrate;

[0122] a resistive switching layer located on the surface of the first electrode away from the substrate;

[0123] a second electrode arranged in an array on the surface of the resistive switching layer away from the substrate;

[0124] The material of the first electrode is inert electrode material Pt.

[0125] The material of the second electrode is active electrode material, the active electrode material is a Ti-Cu alloy, the mass fraction of Ti in the Ti-Cu alloy is 78%, and the rest is Cu (i.e. the mass fraction of Cu is 22%);

[0126] The material of the resistive switching layer is hafnium oxide.

[0127] The substrate comprises a Si / SiO2 / Ti substrate, the substrate comprises a Si layer, a SiO2 layer and a Ti layer which are sequentially stacked, and the first electrode is located on the surface of the Ti layer, wherein the thickness of the Si layer is 500 μm, the thickness of the SiO2 layer is 500 nm, and the thickness of the Ti layer is 50 nm.

[0128] The thickness of the first electrode is 200 nm.

[0129] The thickness of the resistive switching layer is 100 nm.

[0130] The thickness of the second electrode is 250 nm.

[0131] The second electrode has a square shape with a side length of 500 μm.

[0132] The preparation method of the CBRAM device based on the Ti-Cu alloy electrode in Embodiment 3 above comprises the following steps:

[0133] S1, sequentially clean the Si / SiO2 / Ti substrate using acetone for 30 min, anhydrous ethanol for 20 min, and deionized water for 10 min through ultrasonic cleaning, and then dry the substrate for standby use;

[0134] S2, deposit a Pt layer on the cleaned Si / SiO2 / Ti substrate by a magnetron sputtering method to obtain a first electrode, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50 sccm, the pressure in the sputtering cavity is 0.35 Pa, the sputtering power of Pt is 20 W, and the sputtering time of Pt is 1500 s;

[0135] S3, use a hafnium oxide target as a raw material to prepare a resistive switching layer on the surface of the first electrode by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 40 sccm, the pressure in the sputtering cavity is 0.27 Pa, the sputtering power is 35 W, and the sputtering time is 3600 s;

[0136] S4, use a Cu target and a Ti target as raw materials to prepare an array of second electrodes on the surface of the resistive switching layer by a mask and a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50 sccm, the pressure in the sputtering cavity is 0.35 Pa, the sputtering power of Cu is 1 W, the sputtering time of Cu is 1800 s, the sputtering power of Ti is 40 W, and the sputtering time of Ti is 1800 s.

[0137] Comparative Embodiment 1

[0138] Comparative Embodiment 1 provides a preparation method of a CBRAM device based on a Cu electrode, which is the same as Embodiment 1 except that the sputtering power of Ti is 0 W and the sputtering power of Cu is 10 W in step S4, and specifically comprises the following steps:

[0139] S1, sequentially clean the Si / SiO2 / Ti substrate using acetone for 30 min, anhydrous ethanol for 20 min, and deionized water for 10 min through ultrasonic cleaning, and then dry the substrate for standby use;

[0140] S2, depositing a Pt layer on the cleaned Si / SiO2 / Ti substrate by a magnetron sputtering method to obtain a first electrode, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50sccm, the pressure of the sputtering chamber is 0.35Pa, the sputtering power of Pt is 20W, and the sputtering time of Pt is 1500s;

[0141] S3, using a hafnium oxide target as a raw material, a resistive switching layer is prepared on the surface of the first electrode by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 40sccm, the pressure of the sputtering chamber is 0.27Pa, the sputtering power is 35W, and the sputtering time is 3600s;

[0142] S4, using a Cu target and a Ti target as raw materials, a second electrode arranged in an array is prepared on the surface of the resistive switching layer by a mask and a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50sccm, the pressure of the sputtering chamber is 0.35Pa, the sputtering power of Cu is 10W, the sputtering time of Cu is 1800s, the sputtering power of Ti is 0W, and the sputtering time of Ti is 1800s.

[0143] Comparative Example 2

[0144] Comparative Example 2 provides a preparation method of an OxRAM device based on a Ti electrode, which is the same as Example 1, except that in step S4, the sputtering power of Ti is 10W and the sputtering power of Cu is 0W, and specifically comprising the following steps:

[0145] S1, sequentially clean a Si / SiO2 / Ti substrate by ultrasonic cleaning with acetone for 30min, ultrasonic cleaning with anhydrous ethanol for 20min, and ultrasonic cleaning with deionized water for 10min, and then dry the substrate by blowing;

[0146] S2, depositing a Pt layer on the cleaned Si / SiO2 / Ti substrate by a magnetron sputtering method to obtain a first electrode, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 50sccm, the pressure of the sputtering chamber is 0.35Pa, the sputtering power of Pt is 20W, and the sputtering time of Pt is 1500s;

[0147] S3, using a hafnium oxide target as a raw material, a resistive switching layer is prepared on the surface of the first electrode by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are as follows: the temperature is room temperature 25℃, the flow rate of argon is 40sccm, the pressure of the sputtering chamber is 0.27Pa, the sputtering power is 35W, and the sputtering time is 3600s;

[0148] S4, using Cu target and Ti target as raw materials, using mask and using magnetron sputtering method to prepare the second electrode arranged in array on the surface of the resistance change layer, wherein the process parameters controlled during magnetron sputtering are as follows: temperature is room temperature 25℃, flow rate of argon is 50sccm, pressure of sputtering cavity is 0.35Pa, sputtering power of Cu is 0W, sputtering time of Cu is 1800s, sputtering power of Ti is 10W, and sputtering time of Ti is 1800s.

[0149] Performance test

[0150] CBRAM devices / OxRAM devices prepared in Example 1 and Comparative Examples 1-2 are respectively subjected to corresponding performance tests, and all the tests are performed on an Agilent B1500A semiconductor parameter analyzer test platform.

[0151] Specifically, the CBRAM devices in Example 1 and Comparative Example 1 are respectively placed on a probe station, and two probes are respectively contacted with the first electrode and the second electrode of the devices. A direct current scanning voltage of-0.7V-1.5V is applied on the second electrode, and the first electrode is grounded, so as to obtain I-V curves.

[0152] Figure 2 Fig. 1 is an I-V curve diagram of the CBRAM device based on Ti-Cu electrode prepared in Example 1.

[0153] Figure 8 Fig. 2 is an I-V curve diagram of the CBRAM device based on Cu alloy electrode prepared in Comparative Example 1.

[0154] From Figure 2 and Figure 8 It can be seen that the I-V curve shows obvious bipolar resistance transition characteristics and one scanning voltage cycle includes four parts: first scanning from 0V to-0.7V, then scanning from-0.7V to 0V, then scanning from 0V to 1.5V, and finally scanning from 1.5V to 0V, that is, completing one scanning cycle, and the number of scanning steps in each part is 101. In order to prevent the device from being broken down due to too large current during the test, a limiting current of 5mA needs to be set when applying forward voltage. When the voltage is scanned from 0V to-0.7V, it can be seen that the current flowing through the device gradually increases, and when the voltage reaches about-0.6V, the current of the device suddenly decreases, at this time, the device is converted from low resistance state to high resistance state, which is called reset process; when the voltage is scanned from 0V to 1.5V, the current flowing through the device first increases, and when the voltage reaches a certain value, the current flowing through the device suddenly increases, at this time, the device is converted from high resistance state to low resistance state, which is called set process. By comparing Figure 2 and Figure 8It can be seen that the device of Example 1 has more excellent stability, which is due to the use of Ti-Cu alloy electrode instead of Cu electrode, limiting the number of Cu atoms forming conductive filaments injected from the electrode, which can greatly improve the durability of the CBRAM device.

[0155] The resistance values of the high resistance state (HRS) and the low resistance state (LRS) of the CBRAM device of Example 1 and Comparative Example 1 were read at a voltage of -0.098 V, and the resistance distribution diagrams of the two devices were obtained, as shown in Figure 3 and 9 .

[0156] Figure 3 The resistance state distribution diagram of the CBRAM device based on Ti-Cu electrode in Example 1 is shown in

[0157] Figure 9 The resistance state distribution diagram of the CBRAM device based on Cu alloy electrode in Comparative Example 1 is shown in

[0158] It can be seen from Figure 3 and Figure 9 that the R HRS / R LRS of the two devices are about 10, but the device of Comparative Example 1 has begun to appear in the state of device failure at about the 20th cycle, while the device of Example 1 can maintain stable resistance state switching for 300 cycles without failure phenomenon, and the device durability is greatly improved.

[0159] Figure 10 The I-V curve diagram of the OxRAM device based on Ti electrode in Comparative Example 2 is shown in

[0160] The resistance values of the high resistance state and the low resistance state of the OxRAM device based on Ti electrode in Comparative Example 2 were read at a voltage of -0.098 V, and the resistance distribution diagram of the device was obtained, as shown in Figure 11 .

[0161] It can be seen from Figure 11 that the R HRS / R LRSThe uniformity is about 10, but the device of comparative example 2 has begun to appear the state of device failure at about the 35th cycle, while the device of example 1 can maintain stable resistance state switching for 300 cycles without failure, and the device durability is greatly improved. The CBRAM device of Ti-Cu electrode is a conductive filament composed of Cu, and the OxRAM device (i.e., (Oxide Random Access Memory) oxide random access memory) of Ti electrode is a conductive filament composed of oxygen vacancies. Due to the active properties of Ti, under the action of an electric field, the migration of oxygen ions leads to Ti / HfO x interface gradually forms TiO x , and more oxygen vacancies are formed in HfO x , which leads to the need for a stronger electric field to cause the breakage of the conductive filament, so that the Ti-Cu alloy electrode device has better stability than the Ti electrode device.

[0162] Figure 4 is an I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in example 2;

[0163] Figure 5 is a resistance state distribution diagram of the CBRAM device based on the Ti-Cu alloy electrode prepared in example 2;

[0164] Figure 6 is an I-V curve diagram of the CBRAM device based on the Ti-Cu electrode prepared in example 3;

[0165] Figure 7 is a resistance state distribution diagram of the CBRAM device based on the Ti-Cu electrode prepared in example 3.

[0166] It can be seen from Figures 4 to 7 that the stability and consistency of the CBRAM devices prepared in examples 2 and 3 are better than those of the conductive bridge random memory (comparative examples 1 and 2) of pure metal electrodes. Figure 5 and Figure 7 are resistance state distribution diagrams of the devices of examples 2 and 3, respectively, and it can be seen that the Cu-Ti alloy electrode has certain improvement on the durability of the device compared with comparative examples 1 and 2. Among them, the durability of the CBRAM device prepared in example 2 is about 40 cycles, the durability of the CBRAM device prepared in example 3 is about 78 cycles, the durability of the device prepared in comparative example 1 is only 20 cycles, and the durability of the device prepared in comparative example 2 is only 35 cycles.

[0167] Figure 12 is an XPS analysis diagram of the Cu element in the Ti-Cu alloy electrode prepared in example 2.

[0168] Figure 13 XPS analysis graph of Ti element in Ti-Cu alloy electrode prepared in Example 2.

[0169] Figure 14 XPS analysis graph of Cu element in Ti-Cu alloy electrode prepared in Example 3.

[0170] Figure 15 XPS analysis graph of Ti element in Ti-Cu alloy electrode prepared in Example 3.

[0171] Figures 12 to 15 In the above, Experimental represents original data image of XPS analysis, Calculated represents fitting data after calculation and iteration of original data, and Background represents baseline, which mainly provides reliable reference for quantitative analysis.

[0172] From Figure 12 and Figure 13 , it can be calculated that the content of Cu in Example 2 is 99%, from Figure 14 and Figure 15 , it can be calculated that the content of Cu in Example 3 is 22%. From Figure 12 and Figure 14 , it can be seen that Cu in the alloy electrode exists in multiple states, including metallic Cu, CuO2 and CuO. + and Cu 2+ correspond to metallic Cu, CuO2 and CuO. From Figure 13 and Figure 15 , it can be seen that Ti also exists in three states of metallic Ti, TiO2 and TiO. 3+ and Ti 4+ . With the increase of Ti content in Cu-Ti alloy, the content of Cu 2+ increases, that is, more CuO is introduced into the electrode, and CuO is more difficult to release Cu atoms in the redox reaction, so it can limit the injection of Cu atoms from the electrode to the intermediate layer, thereby improving the durability of the device, and the conductive filament is formed by Cu atoms produced by Cu and CuO2.

[0173] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A CBRAM device based on Ti-Cu alloy electrodes, characterized in that: include: substrate; a first electrode, which is located on the surface of the substrate; a resistive switching layer, located on a surface of the first electrode away from the substrate; Second electrodes, whose array is arranged on the surface of the resistive layer away from the substrate; Wherein, the materials of the first electrode and the second electrode are active electrode materials or inert electrode materials. When the material of the first electrode is an active electrode material, the material of the second electrode is an inert electrode material; when the material of the first electrode is an inert electrode material, the material of the second electrode is an active electrode material; The active electrode material is a Ti-Cu alloy; The material of the resistive layer includes any one of hafnium oxide, silicon oxide, zirconium oxide, germanium telluride, and germanium selenide; The mass fraction of Cu in the Ti-Cu alloy is 22-99%, and the remainder is Ti; The inert electrode material includes at least one of Ti, Pt, W, and TiN.

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

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

4. The CBRAM device based on Ti-Cu alloy electrodes according to claim 1, wherein: The thickness of the first electrode is 10-900 nm; The thickness of the resistive switching layer is 1-800 nm; The thickness of the second electrode is 10-900 nm.

5. A method for preparing a CBRAM device based on a Ti-Cu alloy electrode according to any one of claims 1 to 4, characterized in that: The following steps are involved: Prepare a first electrode on the surface of the substrate; A resistive switching layer is prepared on the surface of the first electrode; An array of second electrodes is prepared on the surface of the resistive switching layer.

6. The method for preparing a CBRAM device based on a Ti-Cu alloy electrode according to claim 5, wherein: The Ti-Cu alloy preparation method includes: using a Cu target and a Ti target as raw materials, and preparing the Ti-Cu alloy by a magnetron sputtering method, wherein the process parameters controlled during the magnetron sputtering are: a sputtering chamber pressure of 0.2-0.8 Pa, a sputtering power of Cu of 1-40 W, a sputtering time of Cu of 180-6000 s, a sputtering power of Ti of 1-40 W, and a sputtering time of Ti of 180-6000 s.

7. The method for preparing a CBRAM device based on a Ti-Cu alloy electrode according to claim 5, wherein: The first electrode is prepared by magnetron sputtering, wherein the process parameters controlled during magnetron sputtering are: sputtering chamber pressure of 0.2~0.8Pa, sputtering power of 1~40W, and sputtering time of 180~6000s.

8. The method for preparing a CBRAM device based on a Ti-Cu alloy electrode according to claim 5, wherein: The resistive switching layer is prepared by magnetron sputtering, wherein the process parameters controlled during magnetron sputtering are: sputtering chamber pressure of 0.2~0.8Pa, sputtering power of 1~60W, and sputtering time of 100~7000s.

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