Dual Silicide Technology:WSix Polycide Gate and Self-Aligned CoSi2 Source/Drain

Fabrication of self-aligned silicide of CoSi2 on source/drain areas in a tungsten polycide (WSix/poly) process is demonstrated. CoSi2 is formed by RTA under conditions identical to the poly gate process, i.e. no extra capping layer is required on top of the WSix gate. The materials interactions of WSix with Co films during RTA and subsequent wet etching steps have been studied. Transistor results for 0.5 ¿m NMOS devices are presented.