P-MOSFET's with ultra-shallow solid-phase-diffused drain structure produced by diffusion from BSG gate-sidewall

A p-MOSFET structure with solid-phase diffused drain (SPDD) is proposed for future 0.1- mu m and sub-0.1- mu m devices. Highly doped ultrashallow p/sup +/ source and drain junctions have been obtained by solid-phase diffusion from a highly doped borosilicate glass (BSG) sidewall. The resulting shallow, high-concentration drain profile significantly improves short channel effects without increasing parasitic resistance. At the same time, an in situ highly-boron-doped LPCVD polysilicon gate is introduced to prevent the transconductance degradation which arises in ultrasmall p-MOSFETs with lower process temperature as a result of depletion formation in the p/sup +/-polysilicon gate. Excellent electrical characteristics and good hot-carrier reliability are achieved.<
>