Method of fabricating p-type surface-channel ldmos device with improved in-plane uniformity

Abstract

A method of fabricating a P-type surface-channel laterally diffused metal oxide semiconductor device includes forming a gate structure with polysilicon and metal silicide, and the processes of channel implantation, long-time high-temperature drive-in, formation of a heavily doped N-type polysilicon sinker and boron doping of a polysilicon gate, are performed in this order, thereby ensuring the gate not to be doped with boron during its formation. The high-temperature drive-in process is allowed to be carried out to form a channel with a desired width, and a short channel effect which may cause penetration or electric leakage of the resulting device is prevented. As the polysilicon gate is not processed by any high-temperature drive-in process after it is doped with boron, the penetration of boron through a gate oxide layer and the diffusion of N-type impurity contained in the heavily doped polysilicon sinker into the channel or other regions are prevented.