阅读说明：本技术 一种Ca掺杂碲化锑超稳相变存储薄膜材料及其制备方法 (Ca-doped antimony telluride ultrastable phase change storage thin film material and preparation method thereof ) 是由 陈益敏 毛缘恩 王国祥 侯亚飞 沈祥 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种Ca掺杂碲化锑超稳相变存储薄膜材料及其制备方法,特点是该相变薄膜材料为钙、锑、碲三种元素组成的混合物,其化学结构式为Ca<Sub>x</Sub>(Sb<Sub>2</Sub>Te<Sub>3</Sub>)<Sub>100-x</Sub>,其中0<x<17.6 at%,通过磁控溅射镀膜系统,采用双靶共溅射方式制备得到Ca<Sub>x</Sub>(Sb<Sub>2</Sub>Te<Sub>3</Sub>)<Sub>100-x</Sub>相变存储薄膜材料,优点是该Ca-Sb<Sub>2</Sub>Te<Sub>3</Sub>相变薄膜具有较高的结晶温度、较大的析晶活化能、较好的十年数据保持能力,该相变薄膜具有较高的结晶温度,较大的析晶活化能,较好的十年数据保持力,且电阻漂移系数较低,从而改善相变材料在非晶态下的电阻漂移现象。(The invention discloses a Ca-doped antimony telluride ultrastable phase change storage thin film material and a preparation method thereof, and is characterized in that the phase change thin film material is a mixture consisting of three elements of calcium, antimony and tellurium, and the chemical structural formula of the material is Ca x (Sb 2 Te 3 ) 100‑x Wherein 0 is<x<17.6 at%, and preparing Ca by magnetron sputtering coating system in double-target co-sputtering mode x (Sb 2 Te 3 ) 100‑x Phase changeThe storage thin film material has the advantages of Ca-Sb 2 Te 3 The phase-change film has higher crystallization temperature, larger crystallization activation energy and better ten-year data retention capacity, and has lower resistance drift coefficient, thereby improving the resistance drift phenomenon of the phase-change material in an amorphous state.)

1. A Ca-doped antimony telluride hyperstable phase change storage thin film material is characterized in that: the material is a compound consisting of three elements of calcium, antimony and tellurium.

2. The Ca-doped antimony telluride ultrastable phase change memory thin film material as claimed in claim 1, wherein: the Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_x(Sb₂Te₃)_100-xWherein 0 is<x≤17.6at%。

3. The Ca-doped antimony telluride ultrastable phase change memory thin film material as claimed in claim 2, wherein: the Ca-Sb₂Te₃The thin film material adopts Sb₂Te₃The alloy target and the Ca elementary substance target are formed by co-sputtering.

4. The Ca-doped antimony telluride ultrastable phase change memory thin film material as claimed in claim 2, wherein: the Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_13.6(Sb₂Te₃)_86.4。

5. The Ca-doped antimony telluride ultrastable phase change memory thin film material as claimed in claim 2, wherein: the Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_15.8(Sb₂Te₃)_84.2。

6. The Ca-doped antimony telluride ultrastable phase change memory thin film material as claimed in claim 2, wherein: the Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_17.6(Sb₂Te₃)_82.4。

7. The preparation method of the Ca-doped antimony telluride ultrastable phase change storage thin film material as claimed in any one of claims 1 to 6, which is characterized in that the Ca-doped antimony telluride ultrastable phase change storage thin film material is prepared by a magnetron sputtering coating system and a double-target co-sputtering method, and specifically comprises the following steps:

(1) in a magnetron sputtering coating system, a silicon wafer and a silicon oxide wafer are used as substrates, a Ca target material is arranged in a magnetron radio frequency sputtering target, and an alloy Sb is₂Te₃The target material is arranged in a magnetic control direct current sputtering target;

(2) vacuumizing a sputtering chamber of a magnetron sputtering coating system until the vacuum degree in the chamber reaches 5.0 multiplied by 10^-5Pa, then introducing high-purity argon with the volume flow of 50sccm into the sputtering chamber until the air pressure in the sputtering chamber reaches the air pressure of 0.8Pa required by glow starting;

(3) adjusting the pressure in the chamber to sputtering pressure of 0.4Pa, and controlling the sputtering power of the Ca target material to be 0-35W, and alloying Sb₂Te₃Sputtering target material with sputtering power of 80W at room temperature for 20min to obtain Ca-doped Sb₂Te₃The super stable phase change storage thin film material has the thickness of 400nm and the chemical structural formula of Ca_x(Sb₂Te₃)_100-xWherein 0 is<x≤17.6at%；

(4) Putting the deposited phase change storage thin film material obtained in the step (3) into a rapid annealing furnace, rapidly heating to 200 ℃ and annealing at 300 ℃ respectively under the protection of a high-purity argon atmosphere, and obtaining the heat-treated Ca-doped Sb₂Te₃An ultra stable phase change memory thin film material.

8. The method for preparing the Ca-doped antimony telluride ultrastable phase change material as claimed in claim 7, wherein the method comprises the following steps: the Sb₂Te₃The purity of the target material is 99.99%, and the target material is a cylindrical target material with the diameter of 3 inches and the thickness of 3 millimeters; the purity of the Ca target is 99.5%, and the Ca target is a cylindrical target with the diameter of 3 inches and the thickness of 3 millimeters.

Technical Field

The invention relates to the technical field of phase change storage materials, in particular to a Ca-doped antimony telluride ultrastable phase change storage thin film material and a preparation method thereof.

Background

Information storage plays an important role in human history. Today's electronic technology development has greatly increased the amount of digital data, and it has been reported that the global data scale as low as 2020 will reach 44 gigabytes (approximately equal to 1 trillion GB). The storage, transmission and processing of such huge data groups consumes a lot of resources, and will face a serious challenge in the future. In addition, the erasing time of the most popular non-volatile memory Flash memory (Flash) and volatile Dynamic Random Access Memory (DRAM) is about 5 orders of magnitude (105 ns to 10 ns), which severely restricts the data storage and transmission efficiency, so that a memory revolution is urgently needed to research and develop a non-volatile memory with fast storage, high density and good stability.

Compared with the Flash technology, the phase change memory (PRAM) as a new-generation nonvolatile memory technology has absolute advantages in terms of memory speed and memory density, wherein the memory speed is about 30 ns, and the memory density is as high as 200 Gb/in.²The storage cycle number can reach 10¹²And the method is compatible with the existing CMOS process, and the technical realization difficulty and the industrial cost are lower. In addition, the PRAM storage technology has strong shock resistance and radiation resistance, and has extremely important application prospect in the field of aerospace. The characteristics of PRAM are considered to be the most possible substitution for Flash, and become the next generation of nonvolatile memory, thereby solving the problem of large-capacity data storage and the bottleneck of data storage and transmission efficiency. An important factor determining the performance of the phase change memory is the quality of the phase change material, so that the development of a novel phase change material with excellent performance has important practical application significance in improving the performance of the phase change memory.

Existing conventional Ge₂Sb₂Te₅Although (GST) phase change materials have been widely used in advanced chip technologies such as 3D XPoint developed by intel and meiguang in recent years, many performance defects thereof have not been improved. For example, GST has poor amorphous stability, including a low crystallization temperature, a ten-year data retention temperature, and a structure relaxation phenomenon occurs in amorphous GST, that is, after the GST is placed for a long time, an obvious amorphous resistance drift phenomenon occurs, so that the memory has an unstable amorphous resistance to cause a data storage security problem. That is, the lower amorphous stability and the larger resistance drift of the existing phase change materials hinder further applications of the phase change memory. Therefore, there is a need to research a novel ultra-stable phase change material, i.e., a material having high thermal stability and low resistance drift phenomenon, to solve the above problems. Research shows that the method for improving the thermal stability and reducing the resistance drift phenomenon of the material by selecting proper elements to dope in the matrix of the common phase-change material is a direct and efficient method, and the difficulty is how to find the proper doping elements.

Disclosure of Invention

The invention aims to provide Ca-doped Sb with high thermal stability and lower resistance drift coefficient₂Te₃The material has high crystallization temperature, high crystallization activation energy and high data retention capacity for ten years.

The technical scheme adopted by the invention for solving the technical problems is as follows: a Ca-doped antimony telluride hyperstable phase change storage thin film material is a compound consisting of three elements of calcium, antimony and tellurium.

The Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_x(Sb₂Te₃)_100-xWherein 0 is<x≤17.6at%。

The Ca-Sb₂Te₃The thin film material adopts Sb₂Te₃The alloy target and the Ca elementary substance target are formed by co-sputtering.

The Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_13.6(Sb₂Te₃)_86.4。

The Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_15.8(Sb₂Te₃)_84.2。

The Ca-Sb₂Te₃The chemical structural formula of the film material is Ca_17.6(Sb₂Te₃)_82.4。

The preparation method of the Ca-doped antimony telluride hyperstable phase change storage thin film material is prepared by a magnetron sputtering coating system and a double-target co-sputtering method, and specifically comprises the following steps:

(1) in a magnetron sputtering coating system, a silicon wafer and a silicon oxide wafer are used as substrates, a Ca target material is arranged in a magnetron radio frequency sputtering target, and an alloy Sb is₂Te₃The target material is arranged in a magnetic control direct current sputtering target;

(2) vacuumizing a sputtering chamber of a magnetron sputtering coating system until the vacuum degree in the chamber reaches 5.0 multiplied by 10^-5Pa, then introducing high-purity argon with the volume flow of 50sccm into the sputtering chamber until the air pressure in the sputtering chamber reaches the air pressure of 0.8Pa required by glow starting;

(3) adjusting the pressure in the chamber to sputtering pressure of 0.4Pa, and controlling the sputtering power of the Ca target material to be 0-35W, and alloying Sb₂Te₃Sputtering target material with sputtering power of 80W at room temperature for 20min to obtain Ca-doped Sb₂Te₃The super stable phase change storage thin film material has the thickness of 400nm and the chemical structural formula of Ca_x(Sb₂Te₃)_100-xWherein 0 is<x≤17.6at%；

(4) Putting the deposited phase change storage thin film material obtained in the step (3) into a rapid annealing furnace, rapidly heating to 200 ℃ and annealing at 300 ℃ respectively under the protection of a high-purity argon atmosphere, and obtaining the heat-treated Ca-doped Sb₂Te₃An ultra stable phase change memory thin film material.

The Sb₂Te₃The purity of the target material is 99.99 percent, and the size of the target materialA cylindrical target material with the diameter of 3 inches and the thickness of 3 mm; the purity of the Ca target is 99.5%, and the Ca target is a cylindrical target with the diameter of 3 inches and the thickness of 3 millimeters.

Compared with the prior art, the invention has the advantages that: invented Ca-doped Sb₂Te₃The chemical structural formula of the ultra-stable phase thinned membrane material is Ca_x(Sb₂Te₃)_100-xWherein 0 is<x is less than or equal to 17.6 at%, the phase change film has higher crystallization temperature, larger crystallization activation energy, better ten-year data retention and lower resistance drift coefficient, thereby improving the resistance drift phenomenon of the phase change material in an amorphous state. Wherein Ca obtained by optimization screening_13.6(Sb₂Te₃)_86.4The crystallization temperature of the phase-change film is 225 ℃, the crystallization activation energy is 2.31eV, the ten-year data retention temperature is 121 ℃, particularly, the amorphous resistance drift coefficient is only 0.0044, which is far better than that of the traditional GST phase-change material, so the material can be regarded as a super-stable phase-change storage material with potential application.

Drawings

FIG. 1 shows the different components Ca_x(Sb₂Te₃)_100-xThe square resistance of the film changes with the temperature;

FIG. 2 shows the different components Ca_x(Sb₂Te₃)_100-xCalculating a result graph of the crystallization activation energy and the data retention temperature of the film;

FIG. 3 shows the different components Ca_x(Sb₂Te₃)_100-xAn X-ray diffraction pattern of the film sample in a deposition state;

FIG. 4 shows Ca_13.6(Sb₂Te₃)_86.4X-ray diffraction patterns of the film sample in a deposition state at different temperatures;

FIG. 5 shows Ca_13.6(Sb₂Te₃)_86.4、Ca_15.8(Sb₂Te₃)_84.2、Ca_17.6(Sb₂Te₃)_82.4The resistance of the phase-change film tested at 50 ℃ is changed along with time.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.