An inorganic-organic hybrid nanoporous thin film resistive random access memory and a preparation method thereof

Abstract

The present invention discloses an inorganic-organic hybrid nanoporous thin film resistive random access memory with a multi-level storage function, belonging to the field of semiconductor microelectronic devices. The resistive random access memory structure of the present invention is a substrate, an active electrode, a resistive random access functional layer, and an inert electrode from bottom to top; the resistive random access functional layer is an inorganic-organic hybrid nanoporous thin film material. The present invention uses molecular layer deposition and atomic layer deposition technology to prepare an inorganic-organic hybrid nanoporous thin film resistive random access memory with a multi-level storage function. The molecular layer deposition and atomic layer deposition technology used are compatible with microelectronic processes and suitable for large-scale integration.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor microelectronic devices, and utilizes molecular layer deposition / atomic layer deposition technology to prepare an inorganic-organic hybrid nanoporous thin film resistive random access memory with a multi-level storage function. Background Art

[0002] Resistive random access memory (RRAM) is a non-volatile memory based on the reversible conversion of the resistance of the resistive material between a high resistance state and a low resistance state under the action of an external electric field. Compared with flash memory, RRAM has the characteristics of high density, high speed, low power consumption, easy three-dimensional integration and storage and computing fusion, and is expected to become the next generation of mainstream storage technology. Among the current emerging storage technologies (such as phase change memory, ferroelectric memory and magnetic random access memory), RRAM technology is more suitable for multi-level storage in storage units, which is conducive to improving the storage density of the memory, reducing the energy consumption of the memory, and improving cost-effectiveness. In recent years, international manufacturers such as TSMC, Crossbar, Intel, Fujitsu, and Samsung have focused on the layout of this technology.

[0003] In previous studies, the resistive switching functional materials of RRAM are mainly inorganic materials, and there are also reports on the use of organic materials and inorganic-organic composite materials for resistive switching memory. However, there are very few research reports on the use of inorganic-organic hybrid materials for resistive switching memory. Inorganic-organic hybrid materials are different from the traditional inorganic-organic composite material system. Inorganic-organic components can achieve molecular-level composites, contain rich and colorful physical and chemical properties, and have the advantages of both inorganic and organic compounds. They have great tunability and flexibility in material structure and performance. Inorganic-organic hybrid nanoporous materials are conducive to the diffusion of metal elements or ions, and show unique performance advantages in metal conductive filament-type resistive switching memory. At present, research in this area is still very rare.

[0004] Atomic layer deposition (ALD) and its subclass molecular layer deposition (MLD) are a new type of material preparation technology that is compatible with semiconductor processes and has unique advantages in the controllable low-temperature deposition of inorganics, organic polymers and inorganic-organic hybrid materials. MLD has the same sequence self-limiting surface reaction mechanism as ALD, and can regulate the molecular structure or functional groups at the molecular scale to grow organic polymers or inorganic-organic hybrid materials. It has similar advantages to ALD, excellent three-dimensional conformality, large-area uniformity, good process repeatability, precise film thickness control, and low deposition temperature. The combination of MLD and ALD is very suitable for the controllable preparation of inorganic-organic hybrid materials. Summary of the invention

[0005] The present invention provides an inorganic-organic hybrid nanoporous thin film resistive random access memory with a multi-level storage function and a preparation method thereof, and uses molecular layer deposition (MLD) or a combination of molecular layer deposition (MLD) and atomic layer deposition (ALD) to controllably prepare an inorganic-organic hybrid nanoporous thin film resistive random access function layer.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A multi-level storage inorganic-organic hybrid nanoporous thin film memristor comprises, from bottom to top, a substrate, an active electrode, a resistive switching functional layer, and an inert electrode; the resistive switching functional layer is made of an inorganic-organic hybrid nanoporous thin film material.

[0008] The thickness of the inorganic-organic hybrid nanoporous film is 20-200 nm, and the material is a zinc-hydroquinone hybrid nanoporous film (Zn-HQ) or a zinc-hydroquinone / metal oxide nano-laminated structure [(Zn-HQ) m / (MO x ) n ] p (m=1-20, n=1-20, p=1-20), the hydroquinone is 1,4-benzene (C 6 H 6 O 2 ); the metal oxide is one of zinc oxide, aluminum oxide, hafnium oxide, titanium oxide, zirconium oxide, silicon oxide, tantalum oxide, and tungsten oxide; the active electrode is one of Ag, Cu, and Ni; the inert electrode is one of Pt, Au, W, Ir, and Mo; the substrate is a semiconductor substrate, an insulator substrate, or a polymer substrate.

[0009] A method for preparing a multi-level storage inorganic-organic hybrid nanoporous thin film resistive random access memory comprises the following steps:

[0010] (1) Preparing a metal active electrode on a substrate by magnetron sputtering, ion beam sputtering or vacuum evaporation with a thickness of 10-200 nanometers;

[0011] (2) growing an inorganic-organic hybrid nanoporous thin film on the bottom electrode layer prepared in step (1) by using a molecular layer deposition technique or a combination of molecular layer deposition and atomic layer deposition;

[0012] (3) Using magnetron sputtering, ion beam sputtering or vacuum evaporation technology, an inert electrode with a thickness of 10-200 nanometers is prepared on the resistive functional layer obtained in step (2) to obtain a complete resistive memory structure.

[0013] The beneficial effects of the present invention are:

[0014] The present invention provides an inorganic-organic hybrid nanoporous thin film resistive random access memory with a multi-level storage function and a preparation method thereof. The inorganic-organic hybrid nanoporous thin film with adjustable pore size and porosity is prepared by molecular layer deposition technology or a combination of molecular layer deposition and atomic layer deposition. The adopted molecular layer deposition and atomic layer deposition technologies are compatible with microelectronic processes and are suitable for large-scale industrial production. By setting different limiting currents, a stable multi-level storage state with non-volatility is achieved, and due to the nanoporous structure in the resistive random access functional layer, a lower operating voltage is obtained that is free from electrical formation, thereby simplifying the peripheral circuit design of the resistive random access memory.

[0015] The present invention prepares an inorganic-organic hybrid nanoporous resistive variable film at a relatively low temperature (170-350°C) through an MLD or MLD / ALD combined process that is compatible with semiconductor processes, laying a foundation for the application of inorganic-organic hybrid materials in high storage density, low power consumption resistive variable memory and enriching the selection of resistive variable materials. Moreover, the MLD one-step method for preparing nanoporous film technology is simple and controllable compared to other processes that require porous templates or post-processing methods to obtain porous films, and has extremely high application value in the field of metal conductive filament type resistive variable memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the resistive memory of the present invention;

[0017] Figure 2 The SEM surface morphology image and cross-sectional image of the hybrid thin film functional layer of the resistive random access memory according to Example 1 of the present invention are shown;

[0018] Figure 3 The XPS and FTIR spectra of the hybrid thin film functional layer of the resistive random access memory in Example 1 of the present invention;

[0019] Figure 4 The voltage-current characteristic test diagram of the resistive memory under a DC scanning voltage of Example 1 of the present invention includes a turn-on (set) and a reset (reset) process;

[0020] Figure 5 This is a cycle tolerance test of the resistive random access memory of Example 1 of the present invention;

[0021] Figure 6 The data retention capability test of the resistive random access memory of the first embodiment of the present invention;

[0022] Figure 7 The resistance change diagram of the resistive memory of Example 1 of the present invention during 30 cycles between four low resistance states and a high resistance state;

[0023] Figure 8The retention time of the resistive random access memory in different resistance states in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail by enumerating examples below. It should be noted that the specific implementation described here is only used to explain the present invention and is not used to limit the present invention.

[0025] Example 1

[0026] An inorganic-organic / hybrid nanoporous thin film resistive random access memory with multi-level storage function, comprising, from bottom to top, a substrate, an active electrode, a resistive random access functional layer, and an inert electrode, such as Figure 1 The resistive switching functional layer is an inorganic-organic hybrid nanoporous film material.

[0027] This embodiment is a preparation process of inorganic-organic hybrid nanoporous thin film resistive random access memory - Pt / Zn-based hydroquinone / Ag / Si. Ag prepared by magnetron sputtering is used as the active electrode, hydroquinone (HQ) is used as the organic precursor, diethyl zinc (DEZ) is used as the metal precursor, and molecular layer deposition (MLD) is used to prepare Zn-based hydroquinone (Zn-HQ) inorganic-organic hybrid nanoporous thin film; Pt prepared by magnetron sputtering is used as the top electrode; the specific preparation steps are as follows:

[0028] 1) The silicon wafer was ultrasonically cleaned in acetone, isopropanol, ethanol, and deionized water for 5 minutes respectively, dried with a nitrogen gun, and Ag was sputtered at room temperature as an active electrode with a thickness of 46 nm.

[0029] 2) A Zn-based hydroquinone porous film is deposited on the active electrode as a resistive functional layer using the MLD one-step method. The process conditions are: growth temperature of 200°C, hydroquinone (HQ) as an organic precursor, and diethylzinc (DEZ) as a metal precursor. The source temperature of HQ is 150°C, and the source temperature of DEZ is room temperature. The cycle sequence of the precursor source is: DEZ (pulse 0.1s / cleaning 5s) + HQ (pulse 8s / cleaning 4s). The carrier gas and cleaning gas of the precursor source are both high-purity nitrogen (purity 99.999%) with a flow rate of 150sccm. By controlling the number of growth cycles, the thickness of the deposited film can be controlled. The above-mentioned Zn-HQ film growth cycle number is 150, and the thickness is 200nm.

[0030] 3) The porous structure of Zn-HQ hybrid nanofilm was characterized by scanning electron microscopy, such as Figure 2 As shown, holes with a pore size of 10 to 15 nm are evenly distributed on the surface of the film, and the pore structure exists evenly throughout the entire film, indicating that the porous structure is naturally formed during the MLD deposition process, rather than being caused by etching effects such as water vapor in the environment.

[0031] 4) The chemical composition and functional group chemical bonds of Zn-HQ hybrid films were characterized by XPS and FTIR spectra. Figure 3 The XPS spectra of C, O, and Zn in the hybrid film confirm the existence of organic segments (OC=C bonds in phenolic hydroxyl groups) and inorganic components (Zn-O bonds) in the hybrid film, and the atomic ratio of C, O, and Zn is 2.47:2.14:1; the FTIR spectrum of the hybrid film, 1508cm -1 The absorption peak at 1240 cm comes from the stretching vibration of the C=C bond in the HQ benzene ring. -1 The absorption peak at 1093 cm -1 The absorption peak at 401 cm is the stretching vibration of the COC bond of phenyl ether. -1 The absorption peak at is attributed to the Zn-O stretching mode, which verifies the key group in the hybrid film. Then, combined with the liquid chromatography-mass spectrometry, the structural unit of the hybrid is determined to be (ZnO) 2 (Zn-OC 6 H 4 -O), that is, two zinc oxides are connected to one zinc hydroquinone molecule.

[0032] 5) Use DC magnetron sputtering to sputter Pt as an inert electrode. Use a mask plate to sputter a circular electrode with a diameter of 100 microns. The sputtering current is 30mA and the sputtering time is 400s. In the actual operation process, conductive metal materials such as gold (Au) or ruthenium (Ru) can be used to prepare the inert electrode of the resistive random access memory by DC sputtering and evaporation deposition process. Scrape the edge of the device and apply silver glue to lead out the active electrode for testing.

[0033] 6) The resistive random access memory of the embodiment was tested using a Keithly 4200 semiconductor parameter analyzer. All scanning voltages and pulse voltage signals were applied to the Pt inert electrode, and the Ag active electrode was kept grounded. The scanning voltage of 0V→+2V→0V→-1V→0V was continuously applied, and the voltage-current test was performed for 300 cycles to obtain Figure 4 The IV curve shown is a typical bipolar resistive switching behavior exempted from electrical formation. The SET voltage is very low, only -0.2V, because in the SET process, the conductive filaments are formed by rapid diffusion along the pores in the Zn-HQ porous membrane. As long as a Ag conductive filament is formed locally, it enters a low resistance state.

[0034] 7) The Keithly 4200 semiconductor parameter analyzer was used to perform a cycle tolerance test on the resistive random access memory of the embodiment. Figure 5As shown in the figure, the device can maintain at least 320 resistance changes, the device switching ratio is greater than 100, and the low resistance level is relatively constant, about 60Ω, indicating that there are through-going Ag conductive filaments; while the high resistance is within a certain range (10 4 ~10 6 Ω) fluctuates and shows a gradually increasing trend, indicating that the disconnection of the conductive filaments has a certain randomness due to the complex pore structure.

[0035] 8) The device also exhibits good data retention, such as Figure 6 As shown, the resistance value of the resistive memory is continuously read with a voltage of 0.1V for 10 3 After a few seconds, the high and low resistance values ​​are still very stable and clearly distinguishable, confirming the non-volatility of the high and low resistance states.

[0036] 9) By adjusting the size of the limiting current during the SET process, we studied the multi-value storage characteristics of the resistive random access memory. When measuring the IV characteristics of the device in step 6), a limiting current of 5mA was set to prevent breakdown. In order to obtain the maximum on state of the device, we first removed the limiting current and found that the device can complete the complete SET and RESET process and continue to work for at least 30 cycles. Then we set the limiting current (Icc) to 5mA, 2mA, and 0.5mA respectively, so that the device can be opened to different degrees, and perform 30 switching cycles under different limiting currents, and finally obtain 4 low-resistance values ​​under different SET degrees (such as Figure 7 As shown in Figure 2, it decreases continuously with the increase of limiting current, showing the potential of multi-level data storage.

[0037] 10) Test the data retention capability of each resistance state in step 9), such as Figure 8 As shown, each resistance state is 10 3 s, indicating that the multi-level data storage characteristics of the resistive random access memory are non-volatile.

[0038] Example 2

[0039] This embodiment is an inorganic-organic hybrid nano-laminated porous thin film resistive random access memory - Au / [(Zn-HQ) m (ZnO) n ] p / Cu / quartz glass preparation process (m=5, n=5, p=20). Cu prepared by vacuum evaporation is used as the active electrode, hydroquinone (HQ) is used as the organic precursor, diethyl zinc (DEZ) is used as the metal precursor, deionized water is used as the oxygen source, molecular layer deposition (MLD) is used to prepare zinc-based hydroquinone (Zn-HQ), atomic layer deposition (ALD) is used to prepare zinc oxide (ZnO), and the pore size and porosity of inorganic-organic hybrid nano-laminated porous films are prepared by combining MLD and ALD; Au prepared by vacuum evaporation is used as the inert electrode. The specific preparation steps are as follows:

[0040] 1) The quartz glass was ultrasonically cleaned in acetone, isopropanol, ethanol, and deionized water for 5 minutes respectively, dried with a nitrogen gun, and vacuum evaporated Cu as an active electrode with a thickness of 150 nm.

[0041] 2) Deposition on the active electrode using a combination of MLD and ALD (Zn-HQ) m (ZnO) n Nanolaminated porous film. The process conditions are: growth temperature of 300℃, source temperature of HQ of 150℃, source temperature of DEZ and water of room temperature. The sub-cycle sequence of precursor source is: [DEZ (pulse 0.1s / cleaning 5s) + HQ (pulse 8s / cleaning 4s)] × 5 + [DEZ (pulse 0.1s / cleaning 3s) + H 2 O (pulse 0.1s / cleaning 3s)]×5; the number of super cycles is 20. The carrier gas and cleaning gas of the precursor source are both high-purity nitrogen (purity 99.999%), with a flow rate of 150sccm. By controlling the total growth cycle number, the thickness of the deposited film can be controlled. The above (Zn-HQ) m (ZnO) n The thickness of the nanolaminated porous film is about 130 nm.

[0042] 3) Use ion beam sputtering to sputter Au as an inert electrode. Use a mask plate to sputter a circular electrode with a diameter of 100 microns. Scrape the edge of the device with a diamond knife and apply silver glue to lead out the active electrode for testing.

[0043] Example 3

[0044] This embodiment is an inorganic-organic hybrid nano-laminated porous thin film resistive random access memory - Ir / [(Zn-HQ) m (AlO x ) n ] pPreparation process of / Ni / polyimide (PI). Ni prepared by magnetron sputtering was used as the active electrode, hydroquinone (HQ) was used as the organic precursor, diethylzinc (DEZ) and trimethylaluminum (TMA) were used as the metal precursors, deionized water was used as the oxygen source, molecular layer deposition (MLD) was used to prepare zinc-based hydroquinone (Zn-HQ), atomic layer deposition (ALD) was used to prepare aluminum oxide (AlO x ), an inorganic-organic hybrid nano-laminated porous film with adjustable pore size and porosity is prepared by combining MLD and ALD; Ir prepared by magnetron sputtering is used as an inert electrode; the specific preparation steps are as follows:

[0045] 1) The polyimide was ultrasonically cleaned in acetone, isopropanol, ethanol, and deionized water for 5 minutes respectively, dried with a nitrogen gun, and magnetron sputtered with Ni as an active electrode with a thickness of 20 nm.

[0046] 2) Deposition on the active electrode using a combination of MLD and ALD (Zn-HQ) m (AlO x ) n Nanolaminated porous film. The process conditions are: growth temperature of 170℃, source temperature of HQ of 150℃, source temperature of DEZ, TMA and water of room temperature. The sub-cycle sequence of precursor source is: [DEZ (pulse 0.1s / cleaning 5s) + HQ (pulse 8s / cleaning 4s)] × 10 + [TMA (pulse 0.1s / cleaning 3s) + H 2 O (pulse 0.1s / cleaning 3s)]×2; the number of super cycles is 5. The carrier gas and cleaning gas of the precursor source are both high-purity nitrogen (purity 99.999%), with a flow rate of 150sccm. By controlling the total growth cycle number, the thickness of the deposited film can be controlled. The above (Zn-HQ) m (AlO x ) n The thickness of the nanolaminated porous film is about 50 nm.

[0047] 3) Magnetron sputtering was used to grow Ir as an inert electrode. A circular electrode with a diameter of 100 microns was sputtered using a mask. The edge of the device was scraped with a diamond knife and coated with silver glue to lead out the active electrode for testing.

[0048] The above is only a preferred embodiment of the present invention. The metal oxide in the present invention is one of zinc oxide, aluminum oxide, hafnium oxide, titanium oxide, zirconium oxide, silicon oxide, tantalum oxide, and tungsten oxide; the active electrode is one of Ag, Cu, and Ni; the inert electrode is one of Pt, Au, W, Ir, and Mo; the substrate is one of a semiconductor substrate, an insulator substrate, or a polymer substrate, and the same applies to the above-mentioned embodiment steps. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. An inorganic-organic hybrid nanoporous thin film resistive random access memory, It is characterized in that The resistive random access memory structure includes a substrate, an active electrode, a resistive random access functional layer, and an inert electrode from bottom to top; the resistive random access functional layer is an inorganic-organic hybrid nanoporous film material; the thickness of the inorganic-organic hybrid nanoporous film is 20 to 200 nm, and the inorganic-organic hybrid nanoporous film is prepared from the following materials: a zinc-based hydroquinone hybrid nanoporous film (Zn-HQ) or a zinc-hydroquinone / metal oxide nano-laminated structure [(Zn-HQ) m / (MO x ) n ] p Wherein, m=1-20, n=1-20, p=1-20; The hydroquinone is 1,4-benzene (C 6 H 6 O 2 ); the metal oxide is one of zinc oxide, aluminum oxide, hafnium oxide, titanium oxide, zirconium oxide, silicon oxide, tantalum oxide and tungsten oxide.

2. The inorganic-organic hybrid nanoporous thin film resistive random access memory according to claim 1, It is characterized in that The active electrode is one of Ag, Cu and Ni.

3. The inorganic-organic hybrid nanoporous thin film resistive random access memory according to claim 1, It is characterized in that The inert electrode is one of Pt, Au, W, Ir and Mo.

4. The inorganic-organic hybrid nanoporous thin film resistive random access memory according to claim 1, It is characterized in that The substrate is a semiconductor substrate, an insulator substrate or a polymer substrate.

5. A method for preparing an inorganic-organic hybrid nanoporous thin film resistive random access memory, It is characterized in that The steps of the method are as follows: (1) Preparing a metal active electrode on a substrate by magnetron sputtering, ion beam sputtering or vacuum evaporation with a thickness of 10-200 nanometers; (2) growing an inorganic-organic hybrid nanoporous thin film on the bottom electrode layer prepared in step (1) by using a molecular layer deposition technique or a combination of molecular layer deposition and atomic layer deposition; (3) preparing an inert electrode with a thickness of 10-200 nanometers on the resistive switching functional layer obtained in step (2) by magnetron sputtering, ion beam sputtering or vacuum evaporation to obtain a complete resistive switching memory structure; The inorganic-organic hybrid nanoporous film material is a zinc-hydroquinone hybrid nanoporous film (Zn-HQ) or a zinc-hydroquinone / metal oxide nano-laminated structure [(Zn-HQ) m / (MO x ) n ] p (m=1-20, n=1-20, p=1-20), the hydroquinone is 1,4-benzene (C 6 H 6 O 2 ); the metal oxide is one of zinc oxide, aluminum oxide, hafnium oxide, titanium oxide, zirconium oxide, silicon oxide, tantalum oxide, and tungsten oxide.

6. The method for preparing an inorganic-organic hybrid nanoporous thin film resistive random access memory according to claim 5, It is characterized in that The active electrode is one of Ag, Cu and Ni; the inert electrode is one of Pt, Au, W, Ir and Mo; and the substrate is a semiconductor substrate, an insulator substrate or a polymer substrate.

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