Hole Mobility Enhancement in Strained SiGe Grown on Silicon-on-Insulator p-MOSFETs

Abstract

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-eff) 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-eff. 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-eff 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.