US-12628352-B2 - Threshold switching material, threshold switching device and preparation method thereof

Abstract

A threshold switching material, a threshold switching device and a preparation method thereof are disclosed. The chemical formula of the threshold switching material is M x D 1-x , wherein M is one of La, Ce, Gd, Lu, Sc, Y, Zr, Mo, Hf, W, Ta, D is one of S, Se, Te, and 0.1≤x≤0.8.

Inventors

• Feng Rao
• KEYUAN DING
• Jintao Chen

Assignees

• SHENZHEN UNIVERSITY

Dates

Publication Date

20260512

Application Date

20230904

Priority Date

20221128

Claims (14)

1. 1 . A threshold switching material, which has chemical formula of M x D 1-x , wherein M is one of La, Ce, Gd, Lu, Sc, Y, Zr, Mo, Hf, W and Ta, D is one of S, Se and Te, and 0.1≤x≤0.8.
2. 2 . A threshold switching device, comprising a first electrode, a threshold switching material layer and a second electrode overlapped layer by layer from bottom to top, the threshold switching material layer comprising the threshold switching material according to claim 1 .
3. 3 . The threshold switching device according to claim 2 , wherein the threshold switching device further comprises: a dielectric coating layer coated on a side of a whole of the first electrode, the threshold switching material layer and the second electrode that are overlapped layer by layer.
4. 4 . The threshold switching device according to claim 2 , wherein the threshold switching device further comprises: a substrate having a through hole, the first electrode is disposed in the through hole, and the threshold switching material layer is disposed on the substrate and the first electrode; and a dielectric coating layer coated on a side of a whole of the threshold switching material layer and the second electrode that are overlapped layer by layer.
5. 5 . The threshold switching device according to claim 3 , wherein a material of the first electrode is at least one of W, TiW, TiN and TiSiN.
6. 6 . The threshold switching device according to claim 4 , wherein a material of the first electrode is at least one of W, TiW, TiN and TiSiN.
7. 7 . The threshold switching device according to claim 3 , wherein a material of the second electrode is at least one of W, TiW and TiN.
8. 8 . The threshold switching device according to claim 4 , wherein a material of the second electrode is at least one of W, TiW and TiN.
9. 9 . The threshold switching device according to claim 3 , wherein a material of the dielectric coating layer is at least one of SiO 2 and Si 3 N 4 .
10. 10 . The threshold switching device according to claim 4 , wherein a material of the dielectric coating layer is at least one of SiO 2 and Si 3 N 4 .
11. 11 . The threshold switching device according to claim 3 , wherein a thickness of the threshold switching material layer is in a range of 2 to 40 nm.
12. 12 . The threshold switching device according to claim 4 , wherein a thickness of the threshold switching material layer is in a range of 2 to 40 nm.
13. 13 . The threshold switching device according to claim 4 , wherein a material of the substrate is at least one of SiO 2 and Si 3 N 4 .
14. 14 . A preparation method of a threshold switching device, comprising steps of: providing a first electrode; forming a threshold switching material layer on the first electrode, a material of the threshold switching material layer comprising the threshold switching material according to claim 1 ; and forming a second electrode on the threshold switching material layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a Continuation Application of PCT Application No. PCT/CN2022/142133, filed on Dec. 26, 2022, which claims the priority of Chinese Patent Application No. 202211501433.6, filed on Nov. 28, 2022, the entire contents of which are hereby incorporated by reference. TECHNICAL FIELD The present invention relates to the technical field of semiconductor microelectronics, in particular to a threshold switching material, a threshold switching device and a preparation method thereof. DESCRIPTION OF THE PRIOR ART Memory is an important part of the current semiconductor market, as a cornerstone of information technology, and plays an important role in daily life and the national economy. With the rapid development of the semiconductor industry, the semiconductor technology has also been greatly improved, prompting the device structure to develop in a three-dimensional direction, such as 3D Xpoint and other advanced 3D storage technologies. Compared with traditional 2D storage technology, 3D storage technology has higher storage density, lower power consumption, better service life, faster read and write speed and lower cost. As one of the most potential non-volatile memories of the next generation, phase change memory has advantages of fast read-and-write speed, low operating power consumption, long cycle life, and good resistance to vibration and radiation. In a high-density integrated 3D intersection array, in order to obtain better overall performance, not only memory cells with excellent performance are required, but also switching cells that match the performance of the memory cells are required to eliminate the influence of the leakage current of selected cells on unselected cells. Among various switching cells that can be used as phase change memory cells, the threshold switching device (Ovonic Threshold Switch) using thin films of sulfur compounds as a dielectric is considered to be the most valuable switching device. The threshold switching device mainly includes upper and lower electrode materials, a thin film material of chalcogenide compound with volatile threshold transition characteristics, and an insulating dielectric material that protects the thin film material of chalcogenide compound from oxidation. The working principle of the threshold switching device is to use electrical signals to control the switch of the device, that is, when the applied electrical signals meet certain conditions, the threshold switching material transitions from a high-resistance state to a low-resistance state, so that the threshold switching device is in an open state. Various types of pulse signals can be applied to the phase change memory cells, so that the phase change memory material undergoes a reversible transition between high and low resistance, so as to realize the storage of logic “0” and “1”. When the electrical signals applied to the threshold switching device is lower than a certain value, the threshold switching material transitions from a low-resistance state to a high-resistance state, and the threshold switching device is in an off state, in which state, the leakage current of other cells will not affect the resistance state of the memory cell, ensuring the reliability of information storage. Traditional threshold switching materials are mainly multi-material systems containing As, Se, etc., which have the advantages of good thermal stability, low leakage current, and long cycle life, but they perform poorly in terms of switching speed and driving current. Moreover, multi-component materials are prone to component segregation during the repeated operation of the device, which affects the performance stability of the device. Further, As is toxic. Therefore, it is urgent to develop an environmentally friendly and component-simplified binary threshold switching material system. The reported threshold switching devices based on binary systems such as B—Te, C—Te, and Si—Te have fast switching speeds, but have the problems of low driving current, high leakage current, short cycle life, and poor stability. Therefore, the prior arts still need to be improved and developed. SUMMARY OF THE DISCLOSURE In view of the above-mentioned deficiencies in the prior arts, the object of the present invention is to provide a threshold switching material, a threshold switching device and a preparation method thereof, aiming at solving the problems of low driving current and high leakage current, short cycle life, and poor stability of the threshold switching devices based on the existing binary system-threshold switching materials. Technical solution of the present invention is as follows: The first aspect of the present invention provides a threshold switching material, wherein the chemical formula of the threshold switching material is MxD1-x, wherein M is one of La, Ce, Gd, Lu, Sc, Y, Zr, Mo, Hf, W, Ta, D is one of S, Se, Te, and 0.1≤x≤0.8. The second aspect of th