Hole mobility enhancement in strained SiGe grown on silicon-on-insulator p-MOSFETs

The hole mobility of p-metal-oxide-semiconductor field-effect transistors (MOSFETs) with a compressively-strained SiGe channel grown on a silicon-on-insulator (SOI) structure was investigated. In particular, the dependence of the mobility behavior on the effective field (E_{e f f}) was investigated by varying the Ge concentration in the SiGe layer. We observed that the mobility enhancement factor increased with both the Ge concentration and the E_{e f f}- In addition, we confirmed that the hole mobility enhancement factor caused by the compressively-strained SiGe channel grown on a SOI structure persisted in the higher E_{e f f} range and that it was higher than that of the silicon channel structure. This was due to the fact that the strain and the confinement effects both work to maintain a constant energetic splitting between the heavy hole and the light hole bands.