Optimized Ge channel profiles for VLSI compatible Si/SiGep-MOSFET's

摘要

Theoretical and experimental support is provided to demonstratethat, with the design constraint of a fixed Ge dose, the effective holemobility and carrier confinement in SiGe MOSFET's are maximized byemploying positively graded triangular Ge profiles in the channel. Holemobilities in excess of 400 cm2/Vs were obtainedexperimentally for transistors with 0-50% triangular Ge channelprofiles. When compared to devices with rectangular Ge profiles, theMOSFET's with triangular profiles demonstrated 30-40% improvement inmobility, transconductance and cutoff frequency. These results wereobserved for both MBE- and CVD-grown wafers