Super critical thickness SiGe-channel heterostructure p-type metal-oxide- semiconductor field-effect transistors using laser spike annealing

摘要

Strained Si/strained Si_(0.3)Ge_(0.7)/relaxed Si_(0.7)Ge_(0.3) heterostructure p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) with high mobility and low leakage are demonstrated using laser spike annealing, despite a strained Si_(0.3)Ge_(0.7) channel thickness that is two times the equilibrium critical thickness. Measured hole mobility is enhanced four times for Si_(0.3)Ge_(0.7) channel MOSFETs relative to Si control devices, at an inversion charge density of 10~(13) cm~(-2). For supercritical thickness strained SiGe channel films, the use of laser spike annealing allows source/drain annealing at significantly higher temperatures than is possible with rapid thermal annealing (e.g., 975 versus 800 ℃), while achieving superior leakage characteristics. For laser spike annealing temperatures above 1000 ℃, mobility is found to degrade due to partial relaxation and dislocation formation in the Si_(0.3)Ge_(0.7) channel.