Hole-Mobility Enhancement in Ge-Rich Strained SiGe-on-Insulator pMOSFETs at High Temperatures

Temperature dependence of hole mobility in Ge-rich strained SiGe-on-insulator (SGOI) pMOSFETs was investigated up to 473 K in order to examine the advantage in mobility at temperatures in operating very-large-scale-integrated circuit (VLSI) devices, which are significantly higher than room temperature. High-temperature operation and hole-mobility enhancements are demonstrated up to 473 K for the SGOI-pMOSFETs, which were fabricated by the Ge-condensation technique. The observed drain-current enhancements at 473 K against that of a reference SOI-pMOSFET were almost the same as those at 300 K. Phonon-limited mobility, which ultimately dominates mobility at high temperatures, was extracted by analyzing the temperature dependence of mobility down to 23 K. The extracted phonon-limited mobility exhibited enhancement factors of 12 and 5.5 at 473 K for SGOI devices with Ge fractions of 0.92 and 0.59, respectively, suggesting that such strained-SGOI channels retain the advantage in mobility at elevated temperatures in operating the VLSI devices