HIGH-MOBILITY SI1-XGEX PMOS TRANSISTORS TO 5K

P-channel Si1-xGex MOSFETs with peak Ge content x = 0.3, 0.4, and 0.5 have been fabricated via MBE and experimentally characterized from roo m temperature down to 5K. Mobility enhancements relative to identicall y processed Si controls were largest at the lowest temperatures. The h ighest mobility measured, mu(FE) = 1622 cm2/V.sec for the x = 0.3 SiGe device, was approximately a factor of four higher than the mobility o f the Si control devices. Peak mobility decreased as the fraction of G e in the SiGe channel layer increased for the range of concentrations studied here.