High electron and hole mobility enhancements in thin-body strained Si/strained SiGe/strained Si heterostructures on insulator

Abstract

Fully depleted MOSFETs were fabricated on strained Si/strained SiGe (46% Ge)/strained Si heterostructures on insulator (HOI) for the first time, demonstrating both high electron and hole mobility enhancements while maintaining excellent subthreshold characteristics. The total thickness of the heterostructure on insulator is less than 25 nm. At an inversion charge density of 1.5/spl times/10/sup 13/ cm/sup -2/, mobility enhancements of 90% and 107% are obtained for electrons and holes respectively. The mobility increases as the cap thickness is reduced to 2 nm. HOI offers superior hole mobility than 40% strained silicon directly on insulator at all vertical fields, when the cap thickness is below 5 nm.