A UV-degradable resistive random access memory and a method for preparing the same

Abstract

The present invention discloses a UV-degradable resistive random access memory, which is an electrode / medium / electrode structure, and the resistive random access memory structure is composed of a top electrode, a dielectric layer, a bottom electrode and a substrate from top to bottom; wherein the top electrode is metal copper (Cu), the dielectric layer is a polyphthalaldehyde (cPPA) film, the bottom electrode is indium tin oxide (ITO), and the substrate is a quartz sheet. The resistive random access memory is prepared by using a new polymer polyphthalaldehyde, and the resistive random access memory has a typical bipolar resistive random access characteristic, a high-low resistance ratio, and the device has good cycle durability, and shows reproducible and reliable memory characteristics in terms of data retention and persistence; and the Cu / cPPA / ITO resistive random access memory can achieve the degradation of the resistive random access dielectric layer and the dissolution of the top electrode metal within one hour under ultraviolet light radiation with an illumination of 1000 lux, thereby making the storage device function ineffective, thereby realizing information security storage and environmental protection.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic devices, and in particular to an ultraviolet light degradable resistive random access memory and a preparation method thereof. Background Art

[0002] With the rapid development of information technology, semiconductor memory has become one of the important technologies in the integrated circuit industry and is widely used in various fields of information storage, such as military defense, aerospace, and new energy. Resistive Random Access Memory (RRAM) has become a research hotspot in the semiconductor industry due to its advantages such as fast read and write speed, high storage density, low power consumption, and compatibility with CMOS technology. However, the rapid development of electronic information technology has also brought many problems. First, memory is widely used in many fields of information storage, so the stored information needs to be securely protected; second, an increasing number of electronic products are discarded at the end of their life, resulting in serious environmental pollution, which has become one of the important problems threatening human society.

[0003] Therefore, the study of transient resistive memory is of great significance for secure information storage and environmental protection. As the core component of transient resistive memory, resistive dielectric materials have been reported to have a variety of degradable dielectric layers, including inorganic materials, organic materials and biomaterials. However, most of these degradable materials are based on deionized water dissolution, which is easily affected by humidity in the air and the triggering conditions are uncontrollable. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a UV-degradable resistive random access memory and a preparation method thereof, so as to solve the problem that the conditions for triggering degradation of the transient resistive random access memory in the prior art are relatively harsh and uncontrollable.

[0005] In order to solve the above technical problems, the present invention provides a UV-degradable resistive random access memory, wherein the resistive random access memory is an electrode / dielectric / electrode structure, and the resistive random access memory structure consists of a top electrode, a dielectric layer, a bottom electrode and a substrate from top to bottom, wherein the top electrode is Cu, the dielectric layer is a cPPA film (polyphthalaldehyde), the bottom electrode is ITO, and the substrate is a quartz wafer.

[0006] The present invention also provides a method for preparing a UV-degradable resistive random access memory, and the method for preparing the UV-degradable resistive random access memory comprises the following steps:

[0007] (1) Prepare a spin coating solution: prepare (2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine) (MBTT), poly(o-phthalaldehyde), diethylene glycol dibenzoate and dioxane in a mass volume ratio of (3-20) mg: (100-800) mg: (1-5) mg: (5-20) mL, place the solution in a light-proof container and stir until the poly(o-phthalaldehyde) is completely dissolved, filter the solution and obtain a light yellow transparent solution;

[0008] (2) Treating the ITO-coated glass transparent conductive substrate: sequentially place the ITO-coated glass transparent conductive substrate in toluene, acetone, ethanol and deionized water for continuous ultrasonic treatment for cleaning, and then blow dry for later use;

[0009] (3) Spin coating: Spin coating the light yellow transparent solution obtained in step (1) on the ITO-coated glass transparent conductive substrate, spin coating three layers, and then baking to remove the organic solvent to obtain a cPPA film / ITO glass conductive substrate;

[0010] (4) Sputtering treatment: The Cu electrode is deposited on the cPPA film / ITO glass conductive substrate by a magnetron sputtering process, wherein the thickness of the Cu electrode is 200~700nm, thereby obtaining a Cu / cPPA / ITO resistive random access memory.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. The resistive random access memory prepared by the present invention using polyphthalaldehyde has typical bipolar resistive random access characteristics, a high-low resistance ratio, and the device has good cycle durability; and the Cu / cPPA / ITO resistive random access memory can achieve the dissolution of the resistive random access dielectric layer and the dissolution of the top electrode metal within one hour under ultraviolet light radiation with an illumination of 1000 lux, thereby rendering the memory device function ineffective, thereby achieving information security storage and environmental protection.

[0013] 2. The present invention adopts a spin coating process to prepare a dielectric layer film of a resistive random access memory. The film thickness obtained by spin coating can reach the nm level and the coating thickness is uniform, which can well meet the functional requirements of the device. The top electrode metal copper is deposited by magnetron sputtering technology. The sputtered copper film has high purity, good density, good film uniformity and good bonding with the dielectric layer. The transient resistive random access memory based on the light radiation transient film prepared by spin coating and magnetron sputtering deposition shows non-volatile resistance switching behavior. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural diagram of the ultraviolet light degradable resistive random access memory of the present invention.

[0015] Figure 2This is a physical picture of the Cu / cPPA / ITO resistive memory.

[0016] Figure 3 This is the cross-sectional SEM image of the Cu / cPPA / ITO resistive memory.

[0017] Figure 4 In the figure, (a) is the electrical characteristics of the Cu / cPPA / ITO resistive switching device; (b) is the repeated test result of the Cu / cPPA / ITO device after 50 cycles.

[0018] Figure 5 The electrical performance changes of resistive memory under different radiation time. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] 1. A UV-degradable resistive random access memory

[0021] See also Figures 1 to 3 A UV-degradable resistive random access memory is an electrode / dielectric / electrode structure, and the resistive random access memory structure consists of a top electrode, a dielectric layer, a bottom electrode and a substrate from top to bottom; wherein the top electrode is Cu, the dielectric layer is a cPPA film (i.e., polyphthalaldehyde), the bottom electrode is ITO, and the substrate is a quartz wafer.

[0022] 2. A method for preparing a UV-degradable resistive random access memory

[0023] (1) Prepare spin coating solution: Prepare MBTT (2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine), CPPA (polyphthalaldehyde), DGD (diethylene glycol dibenzoate) and solvent dioxane in a mass volume ratio of (3-20) mg: (100-800) mg: (1-5) mg: (5-20) mL, place in a light-proof container and stir until the polyphthalaldehyde is completely dissolved. Filter through a 0.22 μm pore size Nylon filter to obtain a light yellow transparent solution.

[0024] (2) Treatment of the ITO-coated glass transparent conductive substrate: The ITO-coated glass transparent conductive substrate was placed in toluene, acetone, ethanol and deionized water in turn and continuously ultrasonically treated for 50 minutes for cleaning. After cleaning, it was blown dry with nitrogen for later use;

[0025] (3) Spin coating: Spin coating the light yellow transparent solution obtained in step (1) on the ITO-coated glass transparent conductive substrate, spin coating three layers, and then baking to remove the organic solvent to obtain a cPPA film / ITO glass conductive substrate; wherein the light yellow transparent solution is spin coated on the ITO-coated glass transparent conductive substrate at a rotation speed of 6000-8000 rpm for 30-60 seconds.

[0026] (4) Sputtering treatment: The Cu electrode is deposited on the cPPA film / ITO glass conductive substrate by magnetron sputtering process, wherein the thickness of the Cu electrode is 200~700nm, and the Cu / cPPA / ITO resistive random access memory is obtained. Before sputtering, a mask plate with a circular hole diameter of 200μm is placed on the cPPA film / ITO glass conductive substrate, a copper target material with a purity of 99.99% is used, the Ar gas flow rate is set to 50~70sccm, the sputtering pressure is set to 3~10mT, and the sputtering power is set to 40~80W.

[0027] Table 1

[0028] Example MBTT dosage (mg) CPPA dosage (mg) DGD dosage (mg) Amount of dioxane used (mL) Spin coating time (s) Sputtered Cu thickness (nm) 1 3 100 1 5 30 200 2 10 200 2 10 40 300 3 15 500 4 15 45 500 4 20 300 3 5 50 600 5 20 800 5 20 60 700

[0029] Among them, MBTT is (2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine), which is a photoacid generator; CPPA (polyphthalaldehyde) is the film raw material; DGD (diethylene glycol dibenzoate) is the curing agent; and 1,4-dioxane is the solvent.

[0030] 3. Electrical properties

[0031] The electrical performance of the prepared Cu / cPPA / ITO resistive memory device was characterized, with the positive electrode connected to the Cu electrode and the negative electrode connected to the ITO electrode. Figure 4 (a) shows the IV characteristic curve of the Cu / cPPA / ITO resistive memory device in semi-logarithmic coordinates, and the OFF / ON ratio of the device is about . It shows that through DC voltage cycle scanning, the memory device shows typical bipolar resistive switching characteristics. Figure 4 (b) is the durability of the resistive switching characteristics of the device, where the current values ​​of HRS and LRS were monitored at a readout voltage of 0.2 V. Similar differences between HRS and LRS were maintained for more than 50 cycles.

[0032] 4. Degradation performance

[0033] The degradation performance test experiment of the resistive random access memory prepared in Examples 1 to 5 was carried out. The resistive random access memory device was irradiated with a 365nm ultraviolet lamp (ultraviolet light illumination was about 1000 lux). During the irradiation process, the MBTT in the dielectric layer cPPA film would produce a certain amount of chloride ions under ultraviolet light. These chloride ions combined with hydrogen ions in the environment to form hydrochloric acid. The hydrochloric acid reacted with the acetal skeleton of cPPA to rapidly decompose it, causing the cyclopolyphthalaldehyde (cPPA) to polymerize into a single o-phthalaldehyde (oPA, which is gaseous at room temperature but easily oxidized to an oily substance), so the cPPA film was degraded. When the device is irradiated with ultraviolet light, on the one hand, the dielectric layer (cPPA film) is degraded; on the other hand, the hydrochloric acid formed by the reaction of MBTT in the dielectric layer cPPA film with air will chemically react with the top electrode metal Cu, and the reaction equation is: 2Cu+4HCl=2H[CuCl 2 ]+H 2 ↑, metal Cu reacts with HCl to form CuCl 2 Therefore, under ultraviolet radiation, the metal Cu of the memory top electrode undergoes chemical reaction and the dielectric layer degrades, causing the device to fail.

[0034] like Figure 5 As shown, the resistive memory has no resistive electrical performance after being exposed to ultraviolet light for 1 hour, so its storage function fails.

[0035] The present invention adopts a novel polymer polyphthalaldehyde to prepare a resistive random access memory, and the resistive random access memory based on the cPPA film shows reproducible and reliable memory characteristics in terms of program / erase operation, data retention and persistence; and the Cu / cPPA / ITO resistive random access memory can achieve degradation of the resistive random access dielectric layer and dissolution of the top electrode metal within one hour under ultraviolet light radiation with an illumination of 1000 lux, thereby rendering the memory device functionally ineffective, thereby achieving secure information storage and environmental protection.

[0036] 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 the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A UV-degradable resistive random access memory. It is characterized in that The resistive random access memory is an electrode / dielectric / electrode structure, and the resistive random access memory structure consists of a top electrode, a dielectric layer, a bottom electrode and a substrate from top to bottom; wherein the top electrode is Cu, the dielectric layer is a cPPA film, the bottom electrode is ITO, and the substrate is a quartz sheet; cPPA is cyclopolyphthalaldehyde, and the dielectric layer contains MBTT.

2. A method for preparing a UV-degradable resistive random access memory. It is characterized in that The steps include: (1) preparing a spin coating solution: preparing (2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine), cyclopolyphthalaldehyde, diethylene glycol dibenzoate and dioxane in a mass volume ratio of (3-20) mg: (100-800) mg: (1-5) mg: (5-20) mL, placing the solution in a light-proof container and stirring the solution until the cyclopolyphthalaldehyde is completely dissolved, filtering the solution and obtaining a light yellow transparent solution; (2) Treating the ITO-coated glass transparent conductive substrate: sequentially place the ITO-coated glass transparent conductive substrate in toluene, acetone, ethanol and deionized water for continuous ultrasonic treatment for cleaning, and then blow dry for later use; (3) Spin coating: Spin coating the light yellow transparent solution obtained in step (1) on the ITO-coated glass transparent conductive substrate, spin coating three layers, and then baking to remove the organic solvent to obtain a cPPA film / ITO glass conductive substrate; (4) Sputtering treatment: depositing a Cu electrode on the cPPA film / ITO glass conductive substrate by a magnetron sputtering process, wherein the thickness of the Cu electrode is 200-700 nm, thereby obtaining the UV-degradable resistive random access memory Cu / cPPA / ITO as claimed in claim 1.

3. The method for preparing the UV-degradable resistive random access memory according to claim 2, It is characterized in that In the step (3), the light yellow transparent solution is spin-coated on the ITO-coated glass transparent conductive substrate at a rotation speed of 6000-8000 rpm, and the spin-coating time is 30-60 seconds.

4. The method for preparing the UV-degradable resistive random access memory according to claim 2, It is characterized in that In the step (4), before sputtering, a mask plate with a circular hole diameter of 150-300 μm is placed on the cPPA film / ITO glass conductive substrate, a copper target material with a purity of 99.99% is used, the Ar gas flow rate is set to 50-70 sccm, the sputtering pressure is set to 3-10 mT, and the sputtering power is set to 40-80 W.

5. The method for preparing the UV-degradable resistive random access memory according to claim 2, It is characterized in that After irradiating the Cu / cPPA / ITO resistive random access memory with 365nm ultraviolet light for a period of time, the cPPA film in the Cu / cPPA / ITO resistive random access memory is degraded, causing the storage function of the resistive random access memory to fail.

6. The method for preparing the UV-degradable resistive random access memory according to claim 5, It is characterized in that The UV light intensity is 1000 lux and the irradiation time does not exceed 1h.

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