Method of making a PMOSFET in a semiconductor device

摘要

An improved p+ polysilicon gated PMOSFET having a channel on the surface of a silicon substrate and improved short channel behavior is disclosed. A simplified process allows making a p+ doped gate and source/drain regions at the same time, the transistor particularly having a stable threshold voltage. The disclosed method provides the steps of: (A) forming an active region and an insulation region on an n- type semiconductor substrate; growing a gate insulating layer on the silicon substrate; depositing a polysilicon layer on the gate insulating layer; annealing the polysilicon layer in the presence of NH.sub.3 or other nitrogen-containing gas; (C) forming a gate line by patterning and etching the polysilicon layer; and (D) implanting BF.sub.2 ions into the semiconductor substrate.