Switching operation improvement of phase change memory with nanoscale W plug structure by CMP process

Author

Ying Li ; Zhitang Song ; Bo Liu ; Guanping Wu ; Songlin Feng

Author_Institution

State Key Lab. of Functional Mater. for Inf., Shanghai Inst. of Micro-Syst. & Inf. Technol., Shanghai, China

Volume

49

Issue

12

fYear

2013

fDate

June 6 2013

Firstpage

747

Lastpage

749

Abstract

To reduce the reset current for developing reliable high-density phase change random access memory, small bottom electrode contact (BEC) size formation is a critical process. One of the failure modes for the process is the corrosion of the tungsten (W) plug, which is caused by the W chemical mechanical polisher (CMP) process. An ultra-smooth surface of BEC nanoscale W plug structure was successfully fabricated by the CMP process, which reduced the W/phase change material (Ge₂Sb₂Te₅, GST) contact resistance, and gained more homogeneous resistance distribution. Thus, the stability of the device was improved greatly by the acidic buff CMP process compared with that of the device with alkali buff owing to the reduction of W/GST connect resistance fluctuation.

Keywords

antimony compounds; chemical mechanical polishing; contact resistance; corrosion protection; electrochemical electrodes; failure analysis; germanium compounds; phase change memories; BEC nanoscale W plug structure; BEC size formation; CMP process; GST; Ge₂Sb₂Te₅; chemical mechanical polisher process; contact resistance; corrosion; failure modes; homogeneous resistance distribution; phase change material; phase change random access memory; small bottom electrode contact; switching operation; ultra-smooth surface;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el.2013.0985

Filename

6550135