Investigation and solution of low yield problem for phase change memory with lateral fully-confined structure**Project supported by the National Basic Research Program of China (No. 2011CB922103), the National Natural Science Foundation of China (Nos. 61376420, 61404126, A040203), and the Science and Technology Project of Shenzhen (No. JCYJ20140509172609175).

Abstract

This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor deposition were the main reasons for the poor contact quality, which leads to the low yield problem. Process improvement was carried out to better control over-etching within 10 nm. Atomic layer deposition process was used to replace physical vapor deposition to guarantee good step coverage. Contrasting cross-sectional photos taken by scanning electron microscopy showed great improvement in contact quality. The atom layer deposition process was demonstrated to have good prospects in nano-contact for phase change memory application.