CMOS STRUCTURE WITH BENEFICIAL NMOS AND PMOS BAND OFFSETS

摘要

A CMOS structure with beneficial nMOS and pMOS band offsets is disclosed. A first silicon germanium layer is formed on a semiconductor substrate. A second silicon germanium layer is formed on the first silicon germanium layer. The second silicon germanium layer has a higher germanium percentage than the first silicon germanium layer. Furthermore, the germanium concentration of the two layers is selected such that there is a beneficial band offset for both N-type field effect transistors and P-type field effect transistors in a CMOS structure.

主权项

1. A semiconductor structure comprising:
a semiconductor substrate; a first silicon germanium layer disposed on the semiconductor substrate; a second silicon germanium layer disposed on the first silicon germanium layer; anda plurality of shallow trench isolation regions formed in the second silicon germanium layer and partially into the first silicon germanium layer; wherein the first silicon germanium layer has a first germanium concentration, and wherein the second silicon germanium layer has a second germanium concentration, and wherein the second germanium concentration is greater than the first germanium concentration.