Work function adjustment in high-k gate stacks for devices of different threshold voltage

摘要

In sophisticated semiconductor devices, different threshold voltage levels for transistors may be set in an early manufacturing stage, i.e., prior to patterning the gate electrode structures, by using multiple diffusion processes and/or gate dielectric materials. In this manner, substantially the same gate layer stacks, i.e., the same electrode materials and the same dielectric cap materials, may be used, thereby providing superior patterning uniformity when applying sophisticated etch strategies.