Indium Doped nMOSFETs and Buried Channel pMOSFETs with n+ Polysilicon Gate

Abstract

We have investigated the properties of indium for channel doping engineering. We have fabricated 0.1 µ m super-steep-retrograde (SSR) channel nMOSFETs and buried channel pMOSFETs with an indium counter doping layer. It is found that: (1) Indium is a promising channel dopant when it is implanted into a sub-surface with relatively high energy and its steep profile is maintained throughout the entire process of SSR nMOSFETs. (2) However, it is not practical as a dopant for near-surface p-type conduction layers such as buried channels or p- LDDs in pMOSFETs due to its incomplete ionization and high diffusivity in oxide.