Full Integration of Highly Manufacturable 512Mb PRAM based on 90nm Technology

Fully functional 512Mb PRAM with 0.047μm
²
(5.8F
²
) cell size was successfully fabricated using 90nm diode technology in which we developed novel process schemes such as vertical diode as cell switch, self-aligned bottom electrode contact scheme, and line-type Ge
₂
Sb
₂
Te
₅
. The 512Mb PRAM showed excellent electrical properties of sufficiently large on-current and stable phase transition behavior. The reliability of the 512Mb chip was also evaluated as a write-endurance over 1E5 cycles and a data retention time over 10 years at 85°C.