Method of improving a dual gate cmos transistor to resist the boron-penetrating effect

Abstract

A method of reducing the boron-penetrating of effect in a CMOS transistor provides a silicon substrate, which comprises an isolating area, an active area and a gate oxide layer formed on the silicon substrate in the active layer. A polysilicon layer is then deposited on the silicon substrate. Next, boron ions (B ) are doped into the polysilicon layer. Next, a gate photoresist with a predetermined gate pattern is formed on the polysilicon layer. The polysilicon not covered by the gate photoresist is then etched to form a polysilicon gate. The gate photoresist is used as a mask to dope boron difluoride ions (BF ) into the silicon substrate. Finally, after removing the gate photoresist, a tempering procedure is performed to form a shallow junction area of a source/drain region on the silicon substrate.