Degradation of low frequency noise in SiGe- and SiGeC-surface channel p-type metal-oxide-semiconductor field effect transistor due to consuming the Si cap

Abstract

This letter reports on the noise degradation mechanism in SiGe- and SiGeC-surface channel p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs). Compared to their Si reference, the surface SiGe pMOSFETs show only slightly lower or even comparable noise (at low gate bias), while the SiGeC devices exhibit higher noise amplitude for the full bias range, unlike previously reported buried SiGe pMOSFETs with significantly improved noise over their Si control. The degradation can be attributed to Si-cap consumption and thus the cancellation of buried channel operation. [C] incorporation further degrades noise characteristics due to inferior quality of epilayer and higher interface trap density.