Advanced ring type contact technology for high density phase change memory

Abstract

Advanced bottom electrode contact (BEC) scheme was successfully developed for fabricating reliable high density 64 Mb PRAM by using ring type contact scheme. This advanced ring type BEC scheme was prepared by depositing very thin TiN films inside a contact hole, and then core dielectrics was uniformly filled into the TiN-deposited contact hole. Using this novel contact scheme, it was possible to reduce a reset current with low set resistance, and also maintain a uniform cell distribution. Thus, it is clearly demonstrated that the ring type BEC technology can exhibit strong feasibility of high density 256 Mb PRAM and beyond.