CN-121985733-A - Method for improving performance of chalcogenide bidirectional threshold selector

CN121985733ACN 121985733 ACN121985733 ACN 121985733ACN-121985733-A

Abstract

The invention relates to the technical field of chalcogenide bidirectional threshold value switching devices and discloses a method for improving the performance of a chalcogenide bidirectional threshold value selector, which comprises the following steps that S1, a bottom electrode, an initial amorphous chalcogenide material layer film and a top electrode are sequentially prepared to form a stacked structure, so that the initial chalcogenide bidirectional threshold value selector is obtained; S2, crystallizing, namely placing the initial chalcogenide bidirectional threshold selector obtained in the S1 in an environment higher than 350 ℃ for annealing treatment, so that the initial amorphous chalcogenide material layer film in the initial chalcogenide bidirectional threshold selector is converted into a crystal structure; and S3, carrying out amorphization treatment again, and melting and cooling the chalcogenide material layer film with the crystal structure in S2 to form a second amorphous chalcogenide material layer film with higher order degree than the chalcogenide material layer film with the crystal structure. The sulfur-based bidirectional threshold selector treated by the process of the invention keeps the off-state leakage current stable along with the increase of the cyclic operation.

Inventors

SHI GUANGJIE
CHENG YAN
Xin Tianjiao
ZHENG YONGHUI

Assignees

华东师范大学

Dates

Publication Date: 20260505
Application Date: 20260119

Claims (7)

1. A method of improving the performance of a chalcogenide bidirectional threshold selector comprising the steps of: S1, sequentially preparing a bottom electrode, an initial amorphous chalcogenide material layer film and a top electrode to form a stacked structure, so as to obtain an initial chalcogenide bidirectional threshold selector; S2, crystallizing, namely placing the initial chalcogenide bidirectional threshold selector obtained in the S1 in an environment higher than 350 ℃ for annealing treatment, so that the initial amorphous chalcogenide material layer film in the initial chalcogenide bidirectional threshold selector is converted into a crystal structure; And S3, carrying out amorphization treatment again, and melting and cooling the chalcogenide material layer film with the crystal structure in S2 to form a second amorphous chalcogenide material layer film with higher order degree than the chalcogenide material layer film with the crystal structure.
2. The method of claim 1, wherein the chalcogenide material layer film is a Ge x Se 1-x film.
3. The method for improving the performance of a chalcogenide bidirectional threshold selector according to claim 2, wherein the thickness of the Ge x Se 1-x thin film is 10-50 nm.
4. A method of improving the performance of a chalcogenide bidirectional threshold selector according to claim 3, wherein S2 the annealing treatment is specifically a rapid thermal anneal or a slow anneal in an annealing furnace, and the annealing temperature exceeds the crystallization temperature.
5. A method of enhancing the performance of a chalcogenide two-way threshold selector as claimed in claim 3 wherein said melting of S3 a thin film of chalcogenide material of crystalline structure is performed, in particular by electric pulse or laser.
6. The method of claim 3, wherein the annealing environment of S2 is a vacuum environment having a vacuum level of not less than 10 -3 Pa.
7. The method for improving the performance of a chalcogenide bidirectional threshold value selector according to claim 1, wherein the initial amorphous chalcogenide material layer film of S1 is prepared by any one of magnetron sputtering, pulse laser deposition and electron beam evaporation.

Description

Method for improving performance of chalcogenide bidirectional threshold selector Technical Field The invention relates to the technical field of chalcogenide bidirectional threshold switching devices, in particular to a method for improving the performance of a chalcogenide bidirectional threshold selector. Background With the development of semiconductor memory technology to high density, high speed and low power consumption, a chalcogenide bidirectional threshold switch (OTS) selector becomes an ideal gating device in a high-density memory array by virtue of its bidirectional threshold switching characteristics, fast switching speed (nanosecond level), high on-current and the like. The OTS selector can effectively isolate leakage current of unselected cells and avoid crosstalk phenomenon in the memory array. Among the numerous chalcogenide OTS materials, germanium selenide (GeSe) materials have been widely studied and applied due to their simple composition and strong compatibility of the preparation process. However, existing GeSe-based OTS selectors still suffer from some key performance drawbacks: 1. The off-state current has poor stability, namely, as the cyclic operation is increased, the off-state leakage current is obviously increased, so that the off-state capability of the device is reduced, and further, the misjudgment of the memory array is caused; 2. The fatigue life is short, the effective fatigue frequency of the existing GeSe-based OTS selector is about 10 6 times, and the practical application requirement of high-density storage cannot be met; 3. The core reasons of the problems are that under the condition of multiple electric stress cycles, the GeSe film of the GeSe-based OTS selector is easy to segregate and agglomerate, and the uniformity of an amorphous structure is damaged, so that off-state leakage current is out of control, and fatigue performance is fast attenuated. Currently, schemes aiming at the performance optimization of GeSe-based OTS selectors in industry are mainly focused on doping heterogeneous elements (such As Si and As), and although initial leakage current can be reduced to a certain extent, the Ge/Se atom segregation problem of the GeSe-based OTS selector cannot be fundamentally solved, so that the off-state current stability and the fatigue life are still difficult to break through the bottleneck. Disclosure of Invention Aiming at the defects in the prior art, the method for improving the performance of the chalcogenide bidirectional threshold selector can improve the order of an amorphous GeSe film, reduce the formation of homopolar bonds of Ge-Ge, and fundamentally inhibit the segregation and agglomeration of Ge atoms under the cycle of electric stress. In order to achieve the aim of the invention, the technical scheme adopted by the invention is that the method for improving the performance of the sulfur system bidirectional threshold selector comprises the following steps: S1, sequentially preparing a bottom electrode, an initial amorphous chalcogenide material layer film and a top electrode to form a stacked structure, so as to obtain an initial chalcogenide bidirectional threshold selector; S2, crystallizing, namely placing the initial chalcogenide bidirectional threshold selector obtained in the S1 in an environment higher than 350 ℃ for annealing treatment, so that the initial amorphous chalcogenide material layer film in the initial chalcogenide bidirectional threshold selector is converted into a crystal structure; And S3, carrying out amorphization treatment again, and melting and cooling the chalcogenide material layer film with the crystal structure in S2 to form a second amorphous chalcogenide material layer film with higher order degree than the chalcogenide material layer film with the crystal structure. Further, in the method for improving the performance of the chalcogenide bidirectional threshold selector, the thin film of the chalcogenide material layer is a Ge xSe1-x thin film, wherein x is more than or equal to 0 and less than or equal to 1. Further, in the method for improving the performance of the chalcogenide bidirectional threshold selector, the thickness of the Ge xSe1-x film is 10-50 nm. Further, in the method for improving the performance of the sulfur-based bidirectional threshold selector, the annealing treatment in S2 is specifically rapid thermal annealing or slow annealing in an annealing furnace, and the annealing temperature exceeds the crystallization temperature. Further, in the method for improving the performance of the chalcogenide two-way threshold selector, in S3, the thin film of the chalcogenide material layer with a crystal structure is melted, specifically by electric pulse or laser. Further, in the method for improving the performance of the sulfur-based bidirectional threshold selector, the annealing treatment environment in the step S2 is a vacuum environment, and the vacuum degree of the vacuum environment is not