WO2022110517A1 - Aao template-based sb single-element nanoparticle phase change memory and preparation method therefor - Google Patents

Aao template-based sb single-element nanoparticle phase change memory and preparation method therefor Download PDF

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WO2022110517A1
WO2022110517A1 PCT/CN2021/072092 CN2021072092W WO2022110517A1 WO 2022110517 A1 WO2022110517 A1 WO 2022110517A1 CN 2021072092 W CN2021072092 W CN 2021072092W WO 2022110517 A1 WO2022110517 A1 WO 2022110517A1
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phase change
layer
size
preparation
nano
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程晓敏
曾运韬
靳杰
***
缪向水
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华中科技大学
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N70/00—Solid-state devices having no potential barriers, and specially adapted for rectifying, amplifying, oscillating or switching
    • H10N70/20—Multistable switching devices, e.g. memristors
    • H10N70/231—Multistable switching devices, e.g. memristors based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N70/00—Solid-state devices having no potential barriers, and specially adapted for rectifying, amplifying, oscillating or switching
    • H10N70/011—Manufacture or treatment of multistable switching devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N70/00—Solid-state devices having no potential barriers, and specially adapted for rectifying, amplifying, oscillating or switching
    • H10N70/801—Constructional details of multistable switching devices
    • H10N70/881—Switching materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N70/00—Solid-state devices having no potential barriers, and specially adapted for rectifying, amplifying, oscillating or switching
    • H10N70/801—Constructional details of multistable switching devices
    • H10N70/881—Switching materials
    • H10N70/882—Compounds of sulfur, selenium or tellurium, e.g. chalcogenides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management

Definitions

  • the invention belongs to the technical field of micro-nano electronics, and relates to an information memory, in particular to a method for preparing a Sb single-element nanoparticle phase change memory by using AAO (Anodic Aluminum oxide, AAO) template.
  • AAO Anadic Aluminum oxide
  • DRAM dynamic random access memory
  • DRAM stores information by whether the capacitor is charged with electric charge or not. It is a volatile memory, that is, the data stored in the system will be lost when the system is powered off. , and the charge on the capacitor will slowly disappear over time. Therefore, in order to ensure the safe storage of data, the system must not only keep the power on all the time, but also need to refresh the data regularly, which makes the system energy consumption remain high.
  • Moore's Law continues to approach the physical limit, it is difficult to further increase the capacity of DRAM.
  • phase change memory PCM Phase Change Memory
  • Phase change memory uses the crystalline and amorphous states of chalcogenide compounds to store information, and is a non-volatile memory. Except for read, erase and write operations, the preservation of information does not require power supply maintenance, which has a natural low compared with DRAM. Power consumption advantage; on the other hand, the erasing and writing speed of phase change memory can reach nanosecond or even sub nanosecond level comparable to DRAM; at the same time, with the introduction of 3D-XPoint architecture, the integration and capacity of phase change random access memory There will be a lot of room for improvement.
  • phase change memory and DRAM there is still a big gap between phase change memory and DRAM in terms of the number of cycles to erase and write.
  • the maximum number of cycles of erasing and rewriting PCRAM devices prepared by conventional sputtering processes in the laboratory is 10 9 times.
  • the phase change memory uses chalcogenide as the storage medium, and uses the heat generated by the electrical pulse to convert the material between the crystalline state (SET state, low resistance) and the amorphous state (RESET state, high resistance) to realize the writing and writing of information. Erase. During the cyclic erasing and writing process, the chalcogenide atoms move and diffuse, combine to form bonds or break bonds during repeated melting and cooling processes. Due to the different physical properties of atoms of different elements such as diffusivity under electric field and thermal stress, and the type of ion charge in the molten state, after multiple erasing and writing, atoms of different elements migrate to different electrode directions and form local composition segregation near the electrode.
  • phase change material With the intensification of composition segregation, the structure of the phase change material near different electrodes and the stoichiometric ratio of each element change, resulting in the accumulation or depletion of atoms of a certain element, resulting in the crystalline/amorphous resistance drift of the device.
  • the transport characteristics are changed, and even voids are formed at the interface between the phase change layer and the electrode layer, which eventually leads to the failure of the device. This is the atomic migration failure mechanism of phase change memory.
  • M.Salinga et al. proposed the concept of single-element phase change materials. Obviously, there is only one element in the single-element phase change material, and there is no component segregation phenomenon, so it is expected to fundamentally solve the failure problem of the phase change memory. M.Salinga prepared phase change memory cells with pure Sb phase change layer thicknesses of 3nm, 5nm and 10nm respectively, and realized the erasing and writing of the cells in a liquid nitrogen cooling environment. However, the amorphous stability of the Sb layer at room temperature is not ideal, and the high resistance retention time of the 5nm-thick pure Sb device is only a few seconds.
  • the thinner the thickness of the Sb layer the better the amorphous stability, that is, the one-dimensional confinement in the thickness direction can improve the amorphous stability of the pure Sb phase change layer.
  • the size confinement in one dimension is not enough, and it is necessary to realize the three-dimensional size confinement of the Sb phase change layer to further improve the amorphous stability of the single-element phase change layer.
  • the present invention provides a Sb single-element nanoparticle phase change memory prepared by using AAO template and a preparation method thereof. Limitation, further improve the amorphous stability of the Sb single-element phase change layer, so as to realize the preparation of single-element phase change memory devices; solve the problem of composition segregation after multiple operations of the phase change material, and fundamentally solve the failure of the phase change memory problem.
  • a Sb single-element nanoparticle phase change storage based on AAO template is provided, the phase change layer adopts Sb single-element phase change material, and Sb is filled in the AAO nanopore,
  • the size of the Sb phase change particles in the film plane is limited by the size of the pore size, and the size of the Sb phase change particles on the film thickness is limited by the chemical mechanical polishing process, so as to improve the amorphous stability of the Sb single-element phase change layer.
  • the present invention also provides a preparation method for preparing the Sb single-element nanoparticle phase change storage device by using the AAO template, comprising the following steps:
  • (S2) spin-coating a layer of photoresist on the surface of the metal aluminum layer, and sequentially through a photomask exposure and developing process to form a cell hole array that is not covered and protected by the photoresist, and expose the metal aluminum in the inner layer;
  • step (S4) soaking the nano-sized first-stage porous array in a mixed solution of chromic acid and phosphoric acid, completely removing the porous disordered alumina layer formed in step (S3), and exposing the metal aluminum in the inner layer; In the presence of the porous array, neatly arranged small depressions will be formed on the surface of the inner metal aluminum;
  • the nano-sized second-stage porous array is immersed in a relatively weak corrosive phosphoric acid solution to remove the alumina barrier layer at the bottom of the small hole, and the lower electrode is exposed to obtain a nano-sized hole array with a through-hole structure ;
  • S7 filling Sb single-element material into the nano-sized hole array, and adopting chemical mechanical polishing method to control the size in the vertical direction of the substrate so that the Sb single-element material is limited on the three-dimensional scale;
  • the function of the aperture size of the photoresist mask is to control the oxidation range of the underlying aluminum
  • the aperture of the exposed and developed photoresist is 100nm-300nm
  • the spacing is 100 ⁇ m-500 ⁇ m.
  • the AAO template is prepared by a secondary anodization method to improve the order degree of the porous Al 2 O 3 .
  • the surface of the Al base leaves neatly arranged pits, and the secondary anodization
  • the formed small holes are preferentially formed at the positions corresponding to the pits, and an ordered hole array of nanometer size is obtained.
  • the pore size of AAO can be controlled by changing the electrolyte concentration during preparation. Specifically, with the increase of the electrolyte concentration, the ion concentration gradually increases, the reaction becomes more severe, the volume expansion stress increases, and the formation of pores becomes more orderly, but when the electrolyte concentration is too large, the reaction is too violent, which will cause the temperature The surge reduces the order of the generated holes, and even causes the aluminum foil to be broken down.
  • the pore spacing of AAO can be controlled by changing the oxidation voltage during preparation. There is a linear relationship between the two.
  • the thickness of AAO can be controlled by changing the length of oxidation time.
  • the bottom electrode material is a low work function conductive material with a work function lower than that of the phase change material to form ohmic contact, improve electrical conductivity and reduce electrode heating; preferably, it is composed of one or more of the following materials: Cr, Low work function conductive materials such as Ag, Al, Ti, W, Ni, Mo, and Fe, as well as their oxide and nitride conductive materials, and N-type silicon.
  • the Sb single-element material is deposited by a magnetron sputtering method, and the deposition thickness has a linear relationship with the sputtering time, generally ranging from 10 nm to 20 nm.
  • the dimension in the vertical direction of the device is controlled to be (2 nm ⁇ 10 nm) using the chemical mechanical polishing CMP method.
  • the Sb single-element nanoparticle is located in the pores of the porous alumina Inside.
  • the horizontal size of Sb single-element nanoparticles in the present invention is adjusted by the pore size of porous alumina. Compared with the existing technology of forming a small-sized hole array through a photolithography mask, the present invention is simpler, more efficient and lower in cost.
  • the vertical size of the single-element Sb nanoparticle is adjusted by chemical mechanical polishing (CMP), which limits the vertical size and at the same time makes the surface smoother and improves device performance.
  • CMP chemical mechanical polishing
  • the limitation on the three-dimensional size in the present invention can greatly improve the amorphous stability of the Sb single-element crystal grains, thereby realizing a stable, single-element reversible phase transition with high cycle characteristics.
  • the Sb single-element nanoparticle phase change material and its storage device in the present invention can avoid the problem of component segregation after multiple operations, and fundamentally solve the problem of failure of the phase change memory.
  • a highly corrosive mixed solution of chromic acid and phosphoric acid is used to remove the first-stage hole array to completely remove the first-stage hole array.
  • a less corrosive phosphoric acid solution is used to remove the bottom aluminum oxide barrier layer, so as to achieve the purpose of removing the bottom barrier layer to form a through-hole structure without damaging the second-level hole array structure.
  • FIG. 1 to 9 are schematic diagrams of a preparation process of an information storage device provided by an embodiment of the present invention.
  • FIG. 1 is a schematic diagram of sequentially depositing a bottom electrode and an Al layer on a substrate;
  • FIG. 2 is a schematic view of forming a circular mask by photolithography and development on the Al layer
  • Fig. 3 is the schematic diagram after the Al layer is anodized once to form a nano-sized disordered Al 2 O 3 hole array
  • FIG. 5 is a schematic diagram after the second anodization of the Al layer to form a nano-sized ordered Al 2 O 3 hole array
  • FIG. 6 is a schematic diagram after removing the residual Al barrier layer at the bottom of the small hole
  • Fig. 7 is the schematic diagram after filling Sb material in the nanopore array and polishing with chemical mechanical
  • Fig. 8 is the schematic diagram after degumming treatment and surface flattening
  • FIG. 9 is a schematic diagram of depositing a top electrode material on top of the functional layer to form a complete phase change unit after removing the Al layer;
  • FIG. 10 is a schematic diagram of an AAO template provided by an embodiment of the present invention.
  • each reference sign is as follows: 1 is the substrate (such as a single crystal silicon substrate with an insulating layer of SiO on the surface), 2 is the bottom electrode, 3 is the metal Al layer, 4 is the photoresist mask layer, and 5 is the Alumina (Al 2 O 3 ) layer, 6 is the Sb material, and 7 is the top electrode layer.
  • 1 is the substrate (such as a single crystal silicon substrate with an insulating layer of SiO on the surface)
  • 2 is the bottom electrode
  • 3 is the metal Al layer
  • 4 is the photoresist mask layer
  • 5 is the Alumina (Al 2 O 3 ) layer
  • 6 is the Sb material
  • 7 is the top electrode layer.
  • the invention provides a method for preparing a Sb single - element nanoparticle phase change memory by using an AAO template, which is characterized in that the nanoscale is confined in the pores of porous Al2O3 , and finally the thickness is adjusted by a chemical mechanical polishing method.
  • the size limitation in the three-dimensional direction is realized, and the amorphous stability of the single-element Sb crystal grains is improved. It provides a possibility for single-element reversible phase-change memory devices with high stability and high cycle characteristics.
  • the AAO template is used to prepare the Sb single-element nanoparticle phase change thin film layer, and the specific preparation process includes the following steps:
  • a SiO 2 /Si(100) substrate with a size of 1 cm ⁇ 1 cm was selected, and the surface and back surfaces were cleaned to remove dust particles, organic and inorganic impurities.
  • a metal aluminum layer was deposited on the cleaned SiO 2 /Si(100) substrate by magnetron sputtering, the aluminum thickness was 100 nm, the background vacuum was evacuated to 10 -4 Pa, and the sputtering pressure was 0.5 Pa.
  • a layer of photoresist is spin-coated on the surface of the metal aluminum layer. Through the photomask exposure and development process, a hole-shaped photoresist mask is formed, and the metal aluminum in the inner layer is exposed.
  • Porous alumina was obtained by anodizing method in 0.3M oxalic acid solution, 20V, 11°C.
  • the first anodized film was removed using a mixed solution of 6 wt % phosphoric acid and 1.8 wt % chromic acid.
  • porous alumina with a pore size of 20 nm and a depth of 30 nm was obtained under the conditions of 0.3 M oxalic acid solution, 20 V, and 11 °C.
  • the alumina barrier layer was removed using a 5 wt% phosphoric acid solution.
  • a magnetron sputtering method was used to deposit Sb single element material into the holes.
  • Residual photoresist template and Sb material deposited on it were removed using acetone, anhydrous ethanol solution.
  • the single-element Sb layer thickness was adjusted using CMP. Obtained Sb single-element nanoparticle phase change thin film layer
  • the AAO template is used to prepare the Sb single-element nanoparticle phase change memory, and the specific preparation process includes the following steps:
  • a SiO 2 /Si(100) substrate with a size of 1 cm ⁇ 1 cm was selected, and the surface and back surfaces were cleaned to remove dust particles, organic and inorganic impurities.
  • the bottom electrode material Ti/Pt was deposited by magnetron sputtering on the cleaned SiO 2 /Si(100) substrate, the thickness was 10/100nm, the power was 100/35W, and the background vacuum was pumped to 10 -4 Pa , the sputtering pressure is 0.5Pa.
  • a metal aluminum layer was sputtered with a thickness of 100 nm, and a layer of photoresist was spin-coated on its surface.
  • Porous alumina was obtained by anodizing method in 0.3M oxalic acid solution, 20V, 11°C.
  • the first anodized film was removed using a mixed solution of 6 wt % phosphoric acid and 1.8 wt % chromic acid.
  • porous alumina with a pore size of 20 nm and a depth of 30 nm was obtained under the conditions of 0.3 M oxalic acid solution, 20 V, and 11 °C.
  • the alumina barrier layer was removed using a 5 wt% phosphoric acid solution.
  • a magnetron sputtering method was used to deposit Sb single element material into the holes.
  • Residual photoresist template and Sb material deposited on it were removed using acetone, anhydrous ethanol solution.
  • the single-element Sb layer thickness was adjusted using CMP.
  • the unoxidized aluminum was etched with a mixture of cupric chloride and hydrochloric acid to prepare the top electrode Pt of the device.
  • the overall preparation of Sb single-element nanoparticle phase change memory device is completed.
  • the present invention does not require a sophisticated photolithography etching process, the operation is simpler, the environmental requirements are relatively low, and the cost is greatly reduced;
  • the limitation on the three-dimensional size in the present invention can greatly improve the amorphous stability of Sb single-element crystal grains;
  • the Sb The single-element nanoparticle phase change material and its storage device can avoid the problem of composition segregation after multiple operations, and fundamentally solve the failure problem of phase change memory.

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Abstract

An AAO template-based Sb single-element nanoparticle phase change memory and a preparation method therefor. By means of introducing an AAO template, Sb single-element phase change particles are limited in the three-dimensional scale, such that the amorphous stability of an Sb single-element phase change layer is improved. The preparation method therefor comprises: depositing a layer of metal aluminum (3) on a bottom electrode layer (2), and forming porous alumina (5) on an exposed portion which is not masked with a photoresist by means of a secondary anodic oxidation method, and then obtaining nano-sized pore arrays; and filling the nanopore array with a single-element Sb material, controlling the scale in the vertical direction by means of a chemical mechanical polishing method, and preparing a top electrode (7) to obtain a phase change storage device based on Sb single-element nanoparticles. By means of the AAO template-based Sb single-element nanoparticle phase change memory, the problem of component segregation occurring after a conventional compound phase change material is operated multiple times is thoroughly eliminated, and the problem of failure of the phase change memory is fundamentally solved.

Description

一种基于AAO模板的Sb单元素纳米颗粒相变储存器及其制备方法A kind of Sb single-element nanoparticle phase change memory based on AAO template and preparation method thereof 【技术领域】【Technical field】
本发明属于微纳米电子技术领域，涉及一种信息存储器，特别是涉及一种利用AAO(Anodic Aluminum oxide，AAO)模板制备Sb单元素纳米颗粒相变储存器的方法。The invention belongs to the technical field of micro-nano electronics, and relates to an information memory, in particular to a method for preparing a Sb single-element nanoparticle phase change memory by using AAO (Anodic Aluminum oxide, AAO) template.
【背景技术】【Background technique】
在当今电子技术以及信息产业飞速发展的时代，全球数据量的急剧增加及神经形态存算一体技术的发展对计算机主存的能耗及容量提出了更高的要求。目前，计算机主存芯片主要为动态随机存储器DRAM(Dynamic Random Access Memory)；DRAM是通过电容内是否充有电荷来存储信息的，为易失性存储器，即***掉电其保存的数据就会丢失，并且电容上的电荷会随时间慢慢消失。因此为了保证数据的安全存储，***不仅必须始终保持通电状态，而且需要对数据进行定期刷新，这使得***能耗居高不下。另外，随着摩尔定律不断逼近物理极限，DRAM的容量也很难再进一步提高。In today's era of rapid development of electronic technology and information industry, the rapid increase of global data volume and the development of neuromorphic storage and computing integration technology have put forward higher requirements on the energy consumption and capacity of computer main memory. At present, the main memory chip of the computer is mainly dynamic random access memory (DRAM); DRAM stores information by whether the capacitor is charged with electric charge or not. It is a volatile memory, that is, the data stored in the system will be lost when the system is powered off. , and the charge on the capacitor will slowly disappear over time. Therefore, in order to ensure the safe storage of data, the system must not only keep the power on all the time, but also need to refresh the data regularly, which makes the system energy consumption remain high. In addition, as Moore's Law continues to approach the physical limit, it is difficult to further increase the capacity of DRAM.
在目前已得到深入研究的几种新兴存储器技术中，相变存储器PCM(Phase Change Memory)被认为是最有可能取代DRAM的候选技术。一方面，相变存储器利用硫系化合物的晶态和非晶态来存储信息，是非易失性存储器，除读擦写操作外，信息的保存不需要供电维持，和DRAM相比具有天然的低功耗优势；另一方面，相变存储器的擦写速度可达到和DRAM相当的纳秒级甚至亚纳秒级；同时，随着3D-XPoint架构的推出，相变随机存储器的集成度及容量将有很大的提升空间。然而，在循环擦写次数方面，相变存储器和DRAM相比仍存在较大差距。目前，实验室利用常规溅射工艺制备的PCRAM器件的最高循环擦写次数为10 9次，即使IBM联合日本 真空采用ALD及限制型工艺将PCRAM器件的循环擦写次数提高至10 12次，也离DRAM大于10 15次的循环寿命有一定距离。 Among several emerging memory technologies that have been intensively studied, phase change memory PCM (Phase Change Memory) is considered to be the most likely candidate technology to replace DRAM. On the one hand, phase change memory uses the crystalline and amorphous states of chalcogenide compounds to store information, and is a non-volatile memory. Except for read, erase and write operations, the preservation of information does not require power supply maintenance, which has a natural low compared with DRAM. Power consumption advantage; on the other hand, the erasing and writing speed of phase change memory can reach nanosecond or even sub nanosecond level comparable to DRAM; at the same time, with the introduction of 3D-XPoint architecture, the integration and capacity of phase change random access memory There will be a lot of room for improvement. However, there is still a big gap between phase change memory and DRAM in terms of the number of cycles to erase and write. At present, the maximum number of cycles of erasing and rewriting PCRAM devices prepared by conventional sputtering processes in the laboratory is 10 9 times. Even if IBM and Japan Vacuum use ALD and limited process to increase the number of erasing and erasing cycles of PCRAM devices to 10 12 times, the There is a certain distance from the cycle life of DRAM greater than 10 15 times.
相变存储器以硫系化合物为存储介质，利用电脉冲产生的热量使材料在晶态(SET状态、低阻)与非晶态(RESET状态、高阻)之间相互转换实现信息的写入和擦除。在循环擦写过程中，硫系化合物原子在反复的熔融和冷却过程中移动扩散、组合成键或断开键合。由于不同元素原子在电场和热应力下的扩散能力、熔融状态下离子带电类型等物理性质不同，多次擦写后，不同元素的原子通过向不同电极方向迁移，在电极附近形成局部成分偏析。随着成分偏析的加剧，不同电极附近相变材料的结构及各元素的化学计量比发生变化，形成某种元素原子的累积或耗尽，导致器件的晶态/非晶态阻值漂移等电输运特性改变，甚至在相变层与电极层界面处形成空洞(void)，最终导致器件的失效。这就是相变存储器的原子迁移(atomic migration)失效机制。The phase change memory uses chalcogenide as the storage medium, and uses the heat generated by the electrical pulse to convert the material between the crystalline state (SET state, low resistance) and the amorphous state (RESET state, high resistance) to realize the writing and writing of information. Erase. During the cyclic erasing and writing process, the chalcogenide atoms move and diffuse, combine to form bonds or break bonds during repeated melting and cooling processes. Due to the different physical properties of atoms of different elements such as diffusivity under electric field and thermal stress, and the type of ion charge in the molten state, after multiple erasing and writing, atoms of different elements migrate to different electrode directions and form local composition segregation near the electrode. With the intensification of composition segregation, the structure of the phase change material near different electrodes and the stoichiometric ratio of each element change, resulting in the accumulation or depletion of atoms of a certain element, resulting in the crystalline/amorphous resistance drift of the device. The transport characteristics are changed, and even voids are formed at the interface between the phase change layer and the electrode layer, which eventually leads to the failure of the device. This is the atomic migration failure mechanism of phase change memory.
为了解决这个矛盾，M.Salinga等人提出了单元素相变材料的概念。显然，单元素相变材料内部只有一种元素存在，不存在成分偏析的现象，因此有望从根本上解决相变存储器的失效问题。M.Salinga制备了纯Sb相变层厚度分别为3nm、5nm、10nm的相变存储单元，并在液氮冷却环境下实现了单元的擦写。然而，在室温时Sb层的非晶稳定性很不理想，5nm厚度纯Sb器件的高阻保持时间只有几秒钟即使在低温工作条件下，器件的循环擦写也只有几十次。研究发现，Sb层厚度越薄，非晶稳定性越好，即在厚度方向上的一维限制可以提高纯Sb相变层的非晶稳定性。但是在一个维度上的尺寸限制是不够的，有必要实现对Sb相变层的三维尺寸限制，以进一步提高单元素相变层的非晶稳定性。To resolve this contradiction, M.Salinga et al. proposed the concept of single-element phase change materials. Obviously, there is only one element in the single-element phase change material, and there is no component segregation phenomenon, so it is expected to fundamentally solve the failure problem of the phase change memory. M.Salinga prepared phase change memory cells with pure Sb phase change layer thicknesses of 3nm, 5nm and 10nm respectively, and realized the erasing and writing of the cells in a liquid nitrogen cooling environment. However, the amorphous stability of the Sb layer at room temperature is not ideal, and the high resistance retention time of the 5nm-thick pure Sb device is only a few seconds. It is found that the thinner the thickness of the Sb layer, the better the amorphous stability, that is, the one-dimensional confinement in the thickness direction can improve the amorphous stability of the pure Sb phase change layer. But the size confinement in one dimension is not enough, and it is necessary to realize the three-dimensional size confinement of the Sb phase change layer to further improve the amorphous stability of the single-element phase change layer.
【发明内容】[Content of the invention]
鉴于以上所述现有技术的缺点，本发明提供了一种利用AAO模板制备Sb单元素纳米颗粒相变存储器及其制备方法，其目的是在器件结构上对Sb 单元素晶粒三维尺度上进行限制，进一步提高Sb单元素相变层的非晶稳定性，从而实现单元素相变储存器件的制备；解决相变材料多次操作之后出现的成分偏析问题，从根本上解决相变存储器的失效难题。In view of the above-mentioned shortcomings of the prior art, the present invention provides a Sb single-element nanoparticle phase change memory prepared by using AAO template and a preparation method thereof. Limitation, further improve the amorphous stability of the Sb single-element phase change layer, so as to realize the preparation of single-element phase change memory devices; solve the problem of composition segregation after multiple operations of the phase change material, and fundamentally solve the failure of the phase change memory problem.
为实现上述目的，按照本发明的一个方面，提供了一种基于AAO模板的Sb单元素纳米颗粒相变储存器，相变层采用Sb单元素相变材料，将Sb填充于AAO纳米孔内，通过孔径的大小限制Sb相变颗粒在薄膜平面的尺寸，采用化学机械抛光工艺限制Sb相变颗粒在薄膜厚度上的尺寸，达到提高Sb单元素相变层非晶稳定性的目的。In order to achieve the above object, according to one aspect of the present invention, a Sb single-element nanoparticle phase change storage based on AAO template is provided, the phase change layer adopts Sb single-element phase change material, and Sb is filled in the AAO nanopore, The size of the Sb phase change particles in the film plane is limited by the size of the pore size, and the size of the Sb phase change particles on the film thickness is limited by the chemical mechanical polishing process, so as to improve the amorphous stability of the Sb single-element phase change layer.
本发明还提供了一种利用AAO模板制备Sb单元素纳米颗粒相变储存器的制备方法，包括以下步骤：The present invention also provides a preparation method for preparing the Sb single-element nanoparticle phase change storage device by using the AAO template, comprising the following steps:
(S1)以衬底的上表面为基面，并在所述基面上沉积一层电极材料作为底电极，在所述底电极上沉积一层金属铝；(S1) using the upper surface of the substrate as a base surface, and depositing a layer of electrode material on the base surface as a bottom electrode, and depositing a layer of metal aluminum on the bottom electrode;
(S2)在金属铝层表面旋涂一层光刻胶，依次通过光掩模曝光、显影工艺形成没有被光刻胶覆盖保护的单元孔阵列，并裸露出里层的金属铝；(S2) spin-coating a layer of photoresist on the surface of the metal aluminum layer, and sequentially through a photomask exposure and developing process to form a cell hole array that is not covered and protected by the photoresist, and expose the metal aluminum in the inner layer;
(S3)通过阳极氧化法将裸露的金属铝层形成多孔无序氧化铝，获得纳米尺寸的第一级多孔阵列；(S3) forming the exposed metal aluminum layer into porous disordered aluminum oxide by anodization to obtain a nano-sized first-level porous array;
(S4)将纳米尺寸的第一级多孔阵列浸泡在铬酸与磷酸混合液中，完全去除步骤(S3)中形成的多孔无序氧化铝层，裸露出里层的金属铝；由于第一级多孔阵列的存在，里层金属铝表面会形成排列整齐的小凹陷；(S4) soaking the nano-sized first-stage porous array in a mixed solution of chromic acid and phosphoric acid, completely removing the porous disordered alumina layer formed in step (S3), and exposing the metal aluminum in the inner layer; In the presence of the porous array, neatly arranged small depressions will be formed on the surface of the inner metal aluminum;
(S5)再次通过阳极氧化使裸露的金属铝在凹陷处择优形成多孔有序氧化铝，并获得纳米尺寸的第二级多孔阵列；(S5) by anodizing again, the exposed metal aluminum is preferentially formed into porous ordered alumina in the depressions, and the second-level porous array of nanometer size is obtained;
(S6)将纳米尺寸的第二级多孔阵列浸泡在腐蚀性相较而言偏弱的磷酸溶液中去除小孔底部氧化铝阻挡层，并裸露出下电极后获得通孔结构的纳米尺寸孔阵列；(S6) The nano-sized second-stage porous array is immersed in a relatively weak corrosive phosphoric acid solution to remove the alumina barrier layer at the bottom of the small hole, and the lower electrode is exposed to obtain a nano-sized hole array with a through-hole structure ;
(S7)向所述纳米尺寸孔阵列内填充Sb单元素材料，并采用化学机械抛光法控制垂直基底方向上的尺寸使得Sb单元素材料三维尺度上均受到限 制；(S7) filling Sb single-element material into the nano-sized hole array, and adopting chemical mechanical polishing method to control the size in the vertical direction of the substrate so that the Sb single-element material is limited on the three-dimensional scale;
(S8)依次使用丙酮溶液和无水乙醇溶液去除掉残留的光刻胶模板以及上面沉积的Sb材料；(S8) sequentially using acetone solution and absolute ethanol solution to remove the residual photoresist template and the Sb material deposited on it;
(S9)使用氯化铜、盐酸溶液去除第一孔阵列周围的Al以及制备器件顶电极后获得完整Sb单元素纳米颗粒相变储存器件。(S9) A complete Sb single-element nanoparticle phase-change storage device was obtained after removing Al around the first hole array with copper chloride and hydrochloric acid solution and preparing the top electrode of the device.
优选地，光刻胶掩模孔径大小的作用是来控制下层铝的氧化范围，曝光显影光刻胶的孔径为100nm～300nm，间距为100μm～500μm。Preferably, the function of the aperture size of the photoresist mask is to control the oxidation range of the underlying aluminum, the aperture of the exposed and developed photoresist is 100nm-300nm, and the spacing is 100μm-500μm.
优选的，使用二次阳极氧化法制备AAO模板，提高多孔Al 2O 3的有序度，一次阳极氧化并去除Al 2O 3后，Al基表面留下排列整齐的凹坑，二次阳极氧化形成的小孔优先在凹坑对应的位置形成，得到纳米尺寸有序的孔阵列。 Preferably, the AAO template is prepared by a secondary anodization method to improve the order degree of the porous Al 2 O 3 . After the first anodization and removal of the Al 2 O 3 , the surface of the Al base leaves neatly arranged pits, and the secondary anodization The formed small holes are preferentially formed at the positions corresponding to the pits, and an ordered hole array of nanometer size is obtained.
优选地，改变制备时的电解液浓度可以控制AAO的孔径大小。具体地，随着电解液浓度的提升，离子浓度逐渐增加，反应更加剧烈体积膨胀应力增大，孔洞的生成变得更加有序，但当电解液浓度过于大时，反应过于剧烈，会导致温度激增，使所产生的孔洞有序度下降，甚至会使铝箔被击穿。Preferably, the pore size of AAO can be controlled by changing the electrolyte concentration during preparation. Specifically, with the increase of the electrolyte concentration, the ion concentration gradually increases, the reaction becomes more severe, the volume expansion stress increases, and the formation of pores becomes more orderly, but when the electrolyte concentration is too large, the reaction is too violent, which will cause the temperature The surge reduces the order of the generated holes, and even causes the aluminum foil to be broken down.
优选地，改变制备时的氧化电压大小可以控制AAO的孔间距。两者存在线性关系。Preferably, the pore spacing of AAO can be controlled by changing the oxidation voltage during preparation. There is a linear relationship between the two.
优选地，改变氧化时间长短可以控制AAO的厚度。Preferably, the thickness of AAO can be controlled by changing the length of oxidation time.
优选地，底电极材料均为功函数低于相变材料的低功函数导电材料形成欧姆接触，改善导电性能，减少电极发热；优选的，是由以下的一种或多种材料构成：Cr、Ag、Al、Ti、W、Ni、Mo、Fe这些低功函数导电材料，以及它们的氧化物、氮化物导电材料，以及N型硅。Preferably, the bottom electrode material is a low work function conductive material with a work function lower than that of the phase change material to form ohmic contact, improve electrical conductivity and reduce electrode heating; preferably, it is composed of one or more of the following materials: Cr, Low work function conductive materials such as Ag, Al, Ti, W, Ni, Mo, and Fe, as well as their oxide and nitride conductive materials, and N-type silicon.
优选地，Sb单元素材料采用磁控溅射方法沉积，沉积厚度与溅射时间呈线性关系，一般为10nm～20nm。Preferably, the Sb single-element material is deposited by a magnetron sputtering method, and the deposition thickness has a linear relationship with the sputtering time, generally ranging from 10 nm to 20 nm.
优选地，使用化学机械抛光CMP方法控制器件垂直方向上的尺度为(2nm～10nm)。Preferably, the dimension in the vertical direction of the device is controlled to be (2 nm˜10 nm) using the chemical mechanical polishing CMP method.
总体而言，通过本发明所构思的以上技术方案与现有技术相比，能够取得下列有益效果：In general, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:
(1)与现有技术中的多元相变储存材料功能层相比，本发明利用AAO模板制备出的新型Sb单元素纳米颗粒相变功能层中，Sb单元素纳米颗粒位于多孔氧化铝的孔洞内。(1) Compared with the multi-phase change storage material functional layer in the prior art, in the new Sb single-element nanoparticle phase change functional layer prepared by using the AAO template, the Sb single-element nanoparticle is located in the pores of the porous alumina Inside.
(2)本发明中Sb单元素纳米颗粒水平尺寸由多孔氧化铝的孔径大小调节。与现有通过光刻掩模形成小尺寸孔阵列工艺技术相比，本发明更简单，更高效，成本更低。(2) The horizontal size of Sb single-element nanoparticles in the present invention is adjusted by the pore size of porous alumina. Compared with the existing technology of forming a small-sized hole array through a photolithography mask, the present invention is simpler, more efficient and lower in cost.
(3)本发明中Sb单元素纳米颗粒垂直尺寸由化学机械抛光方法(CMP)调节，限制垂直方向尺寸的同时，使表面更平整，提升器件性能。(3) In the present invention, the vertical size of the single-element Sb nanoparticle is adjusted by chemical mechanical polishing (CMP), which limits the vertical size and at the same time makes the surface smoother and improves device performance.
(4)本发明中三维尺寸上的限制可以大大提高Sb单元素晶粒的非晶稳定性，从而实现稳定的，高循环特性的单元素可逆相变。(4) The limitation on the three-dimensional size in the present invention can greatly improve the amorphous stability of the Sb single-element crystal grains, thereby realizing a stable, single-element reversible phase transition with high cycle characteristics.
(5)本发明中Sb单元素纳米颗粒相变材料及其储存器件可以避免多次操作之后出现的成分偏析问题，从根本上解决相变存储器的失效难题。(5) The Sb single-element nanoparticle phase change material and its storage device in the present invention can avoid the problem of component segregation after multiple operations, and fundamentally solve the problem of failure of the phase change memory.
(6)本发明中去除第一级孔阵列使用腐蚀性较强的铬酸与磷酸混合液以完全去除第一级孔阵列。去除底部氧化铝阻挡层使用腐蚀性较弱的磷酸溶液，达到去除底部阻挡层形成通孔结构同时不破坏第二级孔阵列结构的目的。(6) In the present invention, a highly corrosive mixed solution of chromic acid and phosphoric acid is used to remove the first-stage hole array to completely remove the first-stage hole array. A less corrosive phosphoric acid solution is used to remove the bottom aluminum oxide barrier layer, so as to achieve the purpose of removing the bottom barrier layer to form a through-hole structure without damaging the second-level hole array structure.
【附图说明】【Description of drawings】
图1到图9是本发明实施例提供的信息存储器件的制备过程示意图；其中，图1为在衬底上依次沉积底电极和Al层后的示意图；1 to 9 are schematic diagrams of a preparation process of an information storage device provided by an embodiment of the present invention; wherein, FIG. 1 is a schematic diagram of sequentially depositing a bottom electrode and an Al layer on a substrate;
图2为在Al层上光刻显影形成圆形掩模的示意图；2 is a schematic view of forming a circular mask by photolithography and development on the Al layer;
图3为Al层一次阳极氧化、形成纳米尺寸无序Al 2O 3孔阵列后的示意图； Fig. 3 is the schematic diagram after the Al layer is anodized once to form a nano-sized disordered Al 2 O 3 hole array;
图4为去除第一次阳极氧化无序Al 2O 3后的示意图； 4 is a schematic diagram after removing disordered Al 2 O 3 in the first anodic oxidation;
图5为Al层第二次阳极氧化、形成纳米尺寸有序Al 2O 3孔阵列后的 示意图； FIG. 5 is a schematic diagram after the second anodization of the Al layer to form a nano-sized ordered Al 2 O 3 hole array;
图6为去除小孔底部残留Al阻挡层后的示意图；6 is a schematic diagram after removing the residual Al barrier layer at the bottom of the small hole;
图7为在纳米孔阵列内填充Sb材料、并用化学机械抛光后的示意图；Fig. 7 is the schematic diagram after filling Sb material in the nanopore array and polishing with chemical mechanical;
图8为去胶处理以及表面平整化后的示意图；Fig. 8 is the schematic diagram after degumming treatment and surface flattening;
图9为去除Al层后在功能层顶端沉积顶电极材料形成完整相变单元的示意图；9 is a schematic diagram of depositing a top electrode material on top of the functional layer to form a complete phase change unit after removing the Al layer;
图10为本发明实施例提供的AAO模板示意图；10 is a schematic diagram of an AAO template provided by an embodiment of the present invention;
各附图标记的含义如下：1为衬底(如表面有SiO 2绝缘层的单晶硅衬底)，2为底电极，3为金属Al层，4为光刻胶掩模层，5为氧化铝(Al 2O 3)层，6为Sb材料，7为顶电极层。 The meaning of each reference sign is as follows: 1 is the substrate (such as a single crystal silicon substrate with an insulating layer of SiO on the surface), 2 is the bottom electrode, 3 is the metal Al layer, 4 is the photoresist mask layer, and 5 is the Alumina (Al 2 O 3 ) layer, 6 is the Sb material, and 7 is the top electrode layer.
【具体实施方式】【Detailed ways】
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as there is no conflict with each other.
本发明提供了一种利用AAO模板制备Sb单元素纳米颗粒相变储存器的方法，其特点为：纳米尺度的被限制沉积在多孔Al 2O 3的孔洞中，最后通过化学机械抛光方法调节厚度从而实现三维方向上的尺寸限制，提高单元素Sb晶粒的非晶稳定性。为高稳定性、高循环特性的单元素可逆相变储存器件提供一种可能性。 The invention provides a method for preparing a Sb single - element nanoparticle phase change memory by using an AAO template, which is characterized in that the nanoscale is confined in the pores of porous Al2O3 , and finally the thickness is adjusted by a chemical mechanical polishing method. Thereby, the size limitation in the three-dimensional direction is realized, and the amorphous stability of the single-element Sb crystal grains is improved. It provides a possibility for single-element reversible phase-change memory devices with high stability and high cycle characteristics.
以下为具体实施例：The following are specific examples:
实施例1Example 1
本实施例中利用AAO模板制备Sb单元素纳米颗粒相变薄膜层，具体制备工艺包括以下步骤：In this embodiment, the AAO template is used to prepare the Sb single-element nanoparticle phase change thin film layer, and the specific preparation process includes the following steps:
选取尺寸为1cm×1cm的SiO 2/Si(100)基片，清洗表面、背面，去除 灰尘颗粒、有机和无机杂质。 A SiO 2 /Si(100) substrate with a size of 1 cm×1 cm was selected, and the surface and back surfaces were cleaned to remove dust particles, organic and inorganic impurities.
(a)将SiO 2/Si(100)基片放置在丙酮溶液中用40W功率的超声振动10分钟，去离子水冲洗。 (a) The SiO 2 /Si(100) substrate was placed in an acetone solution with ultrasonic vibration of 40 W for 10 minutes, and rinsed with deionized water.
(b)将丙酮处理后的基片在乙醇溶液中用40W功率的超声振动10分钟，去离子水冲洗，高纯N 2气吹干表面和背面，得到待溅射基片。 (b) The acetone-treated substrate was vibrated with ultrasonic waves of 40 W in an ethanol solution for 10 minutes, rinsed with deionized water, and the surface and back were dried with high - purity N gas to obtain a substrate to be sputtered.
在已经清洗好的SiO 2/Si(100)基片上使用磁控溅射沉积金属铝层，铝厚度为100nm，本底真空抽至10 -4Pa，溅射气压为0.5Pa。 A metal aluminum layer was deposited on the cleaned SiO 2 /Si(100) substrate by magnetron sputtering, the aluminum thickness was 100 nm, the background vacuum was evacuated to 10 -4 Pa, and the sputtering pressure was 0.5 Pa.
在金属铝层表面旋涂一层光刻胶。通过光掩模曝光、显影工艺，形成孔状的光刻胶掩模，裸露出里层的金属铝。A layer of photoresist is spin-coated on the surface of the metal aluminum layer. Through the photomask exposure and development process, a hole-shaped photoresist mask is formed, and the metal aluminum in the inner layer is exposed.
使用阳极氧化法，在0.3M草酸溶液，20V，11℃条件下得到多孔氧化铝。Porous alumina was obtained by anodizing method in 0.3M oxalic acid solution, 20V, 11°C.
使用6wt％磷酸和1.8wt％铬酸的混合溶液去除第一次阳极氧化膜。The first anodized film was removed using a mixed solution of 6 wt % phosphoric acid and 1.8 wt % chromic acid.
通过第二次阳极氧化，在0.3M草酸溶液，20V，11℃条件下得到多孔氧化铝，孔径大小20nm，深度为30nm。Through the second anodic oxidation, porous alumina with a pore size of 20 nm and a depth of 30 nm was obtained under the conditions of 0.3 M oxalic acid solution, 20 V, and 11 °C.
使用5wt％磷酸溶液去除氧化铝阻挡层。The alumina barrier layer was removed using a 5 wt% phosphoric acid solution.
使用磁控溅射方法向孔内沉积Sb单元素材料。A magnetron sputtering method was used to deposit Sb single element material into the holes.
使用丙酮、无水乙醇溶液去除掉残留的光刻胶模板以及上面沉积的Sb材料。Residual photoresist template and Sb material deposited on it were removed using acetone, anhydrous ethanol solution.
使用CMP调节单元素Sb层厚度。得到Sb单元素纳米颗粒相变薄膜层The single-element Sb layer thickness was adjusted using CMP. Obtained Sb single-element nanoparticle phase change thin film layer
实施例2Example 2
本实施例中利用AAO模板制备Sb单元素纳米颗粒相变储存器，具体制备工艺包括以下步骤：In this embodiment, the AAO template is used to prepare the Sb single-element nanoparticle phase change memory, and the specific preparation process includes the following steps:
选取尺寸为1cm×1cm的SiO 2/Si(100)基片，清洗表面、背面，去除灰尘颗粒、有机和无机杂质。 A SiO 2 /Si(100) substrate with a size of 1 cm×1 cm was selected, and the surface and back surfaces were cleaned to remove dust particles, organic and inorganic impurities.
(a)将SiO 2/Si(100)基片放置在丙酮溶液中用40W功率的超声振动10分钟，去离子水冲洗。 (a) The SiO 2 /Si(100) substrate was placed in an acetone solution with ultrasonic vibration of 40 W for 10 minutes, and rinsed with deionized water.
(b)将丙酮处理后的基片在乙醇溶液中用40W功率的超声振动10分钟，去离子水冲洗，高纯N 2气吹干表面和背面，得到待溅射基片。 (b) The acetone-treated substrate was vibrated with ultrasonic waves of 40 W in an ethanol solution for 10 minutes, rinsed with deionized water, and the surface and back were dried with high - purity N gas to obtain a substrate to be sputtered.
在已经清洗好的SiO 2/Si(100)基片上使用磁控溅射沉积底电极材料Ti/Pt，厚度分别为10/100nm，功率分别为100/35W，本底真空抽至10 -4Pa，溅射气压为0.5Pa。 The bottom electrode material Ti/Pt was deposited by magnetron sputtering on the cleaned SiO 2 /Si(100) substrate, the thickness was 10/100nm, the power was 100/35W, and the background vacuum was pumped to 10 -4 Pa , the sputtering pressure is 0.5Pa.
溅射金属铝层，铝厚度为100nm，并在其表面旋涂一层光刻胶。A metal aluminum layer was sputtered with a thickness of 100 nm, and a layer of photoresist was spin-coated on its surface.
通过光掩模曝光、显影工艺，形成孔状的光刻胶掩模，裸露出里层的金属铝。Through the photomask exposure and development process, a hole-shaped photoresist mask is formed, and the metal aluminum in the inner layer is exposed.
使用阳极氧化法，在0.3M草酸溶液，20V，11℃条件下得到多孔氧化铝。Porous alumina was obtained by anodizing method in 0.3M oxalic acid solution, 20V, 11°C.
使用6wt％磷酸和1.8wt％铬酸的混合溶液去除第一次阳极氧化膜。The first anodized film was removed using a mixed solution of 6 wt % phosphoric acid and 1.8 wt % chromic acid.
通过第二次阳极氧化，在0.3M草酸溶液，20V，11℃条件下得到多孔氧化铝，孔径大小20nm，深度为30nm。Through the second anodic oxidation, porous alumina with a pore size of 20 nm and a depth of 30 nm was obtained under the conditions of 0.3 M oxalic acid solution, 20 V, and 11 °C.
使用5wt％磷酸溶液去除氧化铝阻挡层。The alumina barrier layer was removed using a 5 wt% phosphoric acid solution.
使用磁控溅射方法向孔内沉积Sb单元素材料。A magnetron sputtering method was used to deposit Sb single element material into the holes.
使用丙酮、无水乙醇溶液去除掉残留的光刻胶模板以及上面沉积的Sb材料。Residual photoresist template and Sb material deposited on it were removed using acetone, anhydrous ethanol solution.
使用CMP调节单元素Sb层厚度。The single-element Sb layer thickness was adjusted using CMP.
用氯化铜、盐酸混合液刻蚀掉未被氧化的铝并制备器件顶电极Pt。完成Sb单元素纳米颗粒相变储存器件的整体制备。The unoxidized aluminum was etched with a mixture of cupric chloride and hydrochloric acid to prepare the top electrode Pt of the device. The overall preparation of Sb single-element nanoparticle phase change memory device is completed.
上述实施例中的参数、条件设置等，可行性好，当然仅作为示例。The parameters, condition settings, etc. in the above-mentioned embodiments have good feasibility, and are of course only used as examples.
与现有极细微孔阵列制备方法比较，本发明不需要尖端精细的光刻刻蚀工艺，操作更简单，环境要求相对较低，成本大大降低；与现有在厚度一维方向上调控Sb单元素材料非晶稳定性的方法比较，本发明中三维尺寸上的限制可以大大提高Sb单元素晶粒的非晶稳定性；与现有多元素相变储存功能材料及器件比较，本发明中Sb单元素纳米颗粒相变材料及其储存器 件可以避免多次操作之后出现的成分偏析问题，从根本上解决相变存储器的失效难题。Compared with the existing method for preparing a very fine hole array, the present invention does not require a sophisticated photolithography etching process, the operation is simpler, the environmental requirements are relatively low, and the cost is greatly reduced; Compared with the methods for the amorphous stability of element materials, the limitation on the three-dimensional size in the present invention can greatly improve the amorphous stability of Sb single-element crystal grains; compared with the existing multi-element phase change storage functional materials and devices, the Sb The single-element nanoparticle phase change material and its storage device can avoid the problem of composition segregation after multiple operations, and fundamentally solve the failure problem of phase change memory.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (10)

  1. 一种基于AAO模板的Sb单元素纳米颗粒相变储存器，其特征在于，相变层采用Sb单元素相变材料，将Sb填充于AAO纳米孔内，通过孔径的大小限制Sb相变颗粒在薄膜平面的尺寸，采用化学机械抛光工艺限制Sb相变颗粒在薄膜厚度上的尺寸，达到提高Sb单元素相变层非晶稳定性的目的。An AAO template-based Sb single-element nanoparticle phase change storage is characterized in that the phase change layer adopts Sb single-element phase change material, Sb is filled in the AAO nanopore, and the Sb phase change particle is limited by the size of the pore size. The size of the film plane, the chemical mechanical polishing process is used to limit the size of the Sb phase change particles on the film thickness, so as to improve the amorphous stability of the Sb single-element phase change layer.
  2. 一种基于AAO模板的Sb单元素纳米颗粒相变储存器的制备方法，其特征在于，包括以下步骤：A preparation method of an AAO template-based Sb single-element nanoparticle phase change storage device, characterized in that it comprises the following steps:
    (S1)以衬底的上表面为基面，并在所述基面上沉积一层电极材料作为底电极，在所述底电极上沉积一层金属铝；(S1) using the upper surface of the substrate as a base surface, and depositing a layer of electrode material on the base surface as a bottom electrode, and depositing a layer of metal aluminum on the bottom electrode;
    (S2)在金属铝层表面旋涂一层光刻胶，依次通过光掩模曝光、显影工艺形成没有被光刻胶覆盖保护的单元孔阵列，并裸露出里层的金属铝；(S2) spin-coating a layer of photoresist on the surface of the metal aluminum layer, and sequentially through a photomask exposure and developing process to form a cell hole array that is not covered and protected by the photoresist, and expose the metal aluminum in the inner layer;
    (S3)通过阳极氧化法将裸露的金属铝层形成多孔无序氧化铝，获得纳米尺寸的第一级孔阵列；(S3) forming the exposed metal aluminum layer into porous disordered aluminum oxide by anodizing method to obtain a nano-sized first-order pore array;
    (S4)将纳米尺寸的第一级孔阵列浸泡在铬酸与磷酸混合液中，完全去除步骤(S3)中形成的多孔无序氧化铝层，裸露出里层的金属铝；(S4) soaking the nano-sized first-stage hole array in a mixed solution of chromic acid and phosphoric acid, completely removing the porous disordered alumina layer formed in step (S3), and exposing the metal aluminum in the inner layer;
    (S5)再次通过阳极氧化使裸露的金属铝在凹陷处择优形成多孔有序氧化铝，并获得纳米尺寸的第二级孔阵列；(S5) by anodizing again, the exposed metal aluminum is preferentially formed in the recesses to form porous ordered alumina, and a nano-sized second-order pore array is obtained;
    (S6)将纳米尺寸的第二级孔阵列浸泡在腐蚀性相较而言偏弱的磷酸溶液中去除小孔底部氧化铝阻挡层，并裸露出下电极后获得通孔结构的纳米尺寸孔阵列；(S6) The nano-sized second-order hole array is soaked in a relatively weak corrosive phosphoric acid solution to remove the alumina barrier layer at the bottom of the small hole, and the lower electrode is exposed to obtain a nano-sized hole array with a through-hole structure ;
    (S7)向所述纳米尺寸孔阵列内填充Sb单元素材料，并采用化学机械抛光法控制垂直基底方向上的尺寸使得Sb单元素材料三维尺度上均受到限制；(S7) filling the nano-sized hole array with Sb single-element material, and using a chemical mechanical polishing method to control the size in the direction perpendicular to the substrate, so that the Sb single-element material is limited in three-dimensional scale;
    (S8)依次使用丙酮溶液和无水乙醇溶液去除掉残留的光刻胶模板以 及上面沉积的Sb材料；(S8) use acetone solution and absolute ethanol solution successively to remove residual photoresist template and the Sb material deposited above;
    (S9)使用氯化铜、盐酸溶液去除第一孔阵列周围的Al以及制备器件顶电极后获得完整Sb单元素纳米颗粒相变储存器件。(S9) A complete Sb single-element nanoparticle phase-change storage device was obtained after removing Al around the first hole array with copper chloride and hydrochloric acid solution and preparing the top electrode of the device.
  3. 如权利要求2所述的制备方法，其特征在于，所述步骤(S4)中，沉积的所述单元素相变材料具有相变存储特性。The preparation method according to claim 2, characterized in that, in the step (S4), the deposited single-element phase-change material has phase-change memory properties.
  4. 如权利要求2或3所述的制备方法，其特征在于，形成的氧化铝孔洞三维尺寸均限制在10nm以下。The preparation method according to claim 2 or 3, wherein the three-dimensional size of the formed alumina pores is limited to be less than 10 nm.
  5. 如权利要求4所述的制备方法，其特征在于，在(S7)中，采用化学机械抛光法控制垂直方向上的尺寸为2nm～10nm。The preparation method according to claim 4, characterized in that, in (S7), a chemical mechanical polishing method is used to control the size in the vertical direction to be 2 nm˜10 nm.
  6. 如权利要求2-5任一项所述的方法，其特征在于，在步骤(S2)中曝光显影光刻胶的孔径为100nm～300nm，间距为100μm～500μm。The method according to any one of claims 2-5, characterized in that, in step (S2), the pore size of the exposed and developed photoresist is 100 nm-300 nm, and the spacing is 100 μm-500 μm.
  7. 如权利要求2-6任一项所述的方法，其特征在于，通过改变电解液浓度、氧化电压大小来控制AAO的孔径，并通过调整氧化时间的长短来控制AAO的厚度。The method according to any one of claims 2-6, wherein the pore size of the AAO is controlled by changing the electrolyte concentration and the oxidation voltage, and the thickness of the AAO is controlled by adjusting the length of the oxidation time.
  8. 如权利要求2-7任一项所述的方法，其特征在于，所述底电极材料均为功函数低于相变材料的低功函数的导电材料并形成欧姆接触。The method according to any one of claims 2-7, wherein the bottom electrode material is a conductive material with a work function lower than the low work function of the phase change material and forms an ohmic contact.
  9. 如权利要求8所述的方法，其特征在于，所述底电极材料为以下的一种或多种材料构成：Cr、Ag、Al、Ti、W、Ni、Mo或Fe，以及其氧化物、氮化物导电材料或N型硅。The method of claim 8, wherein the bottom electrode material is composed of one or more of the following materials: Cr, Ag, Al, Ti, W, Ni, Mo or Fe, and their oxides, Nitride conductive material or N-type silicon.
  10. 如权利要求2-9任一项所述的方法，其特征在于，Sb单元素材料采用磁控溅射方法沉积，沉积厚度为10nm～20nm。The method according to any one of claims 2-9, wherein the Sb single-element material is deposited by a magnetron sputtering method, and the deposition thickness is 10 nm-20 nm.
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