Method of forming phase change random access memory (PCRAM) cell

Abstract

A method of forming a phase change random access memory (PCRAM) cell comprises the steps of providing a substrate; forming a dielectric layer on the surface of the substrate; forming a through hole penetrating through the dielectric layer, the through hole comprising a first through hole portion located at the surface of the substrate and a second through hole portion located above the first through hole portion and communicating with the first through hole portion, the first through hole portion having a side wall perpendicular to the surface of the substrate, and the second through hole having an inclined side wall and a larger top width and a smaller bottom width; forming a metal layer on the inner wall surface of the through hole and on the surface of the dielectric layer, the metal layer filling the first through hole portion and covering the side wall of the second through hole portion; forming a sacrificial layer on the surface of the metal layer, the sacrificial layer filling the second through hole portion; carrying out planarization processing, removing the sacrificial layer, a part of the metal layer and a part of the dielectric layer that are over the first through hole portion; and forming a phase change layer on the surface of the remaining dielectric layer and the surface of the metal layer in the first through hole portion. The above method can improve the performance of the formed PCRAM cell.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for forming a phase-change memory unit. Background technique [0002] Phase Change Random Access Memory (PCRAM) technology is established based on the idea that phase change thin films can be applied to phase change storage media. As an emerging non-volatile storage technology, phase change memory has great advantages over flash memory in many aspects such as read and write speed, read and write times, data retention time, unit area, and multi-value realization. Become the focus of current non-volatile memory technology research. [0003] In phase-change memory, the storage value of the memory can be changed by heat-treating the phase-change layer on which data is recorded. The phase change material constituting the phase change layer enters a crystalline state or an amorphous state due to the heating effect of an applied electric current. When the phase change...

AI Technical Summary

Problems solved by technology

[0007] At present, TiN is usually used as the material of the bottom contact electrode 21, and the performance of the phase change memory cell needs to be further improved.

Images