SUBBAND STRUCTURE AND MOBILITY OF 2-DIMENSIONAL HOLES IN STRAINED SI SIGE MOSFETS/

The hole mobility of p-type strained Si metal-oxide-semiconductor fiel d-effect transistors (MOSFET's) fabricated on a SiGe substrate is inve stigated theoretically and compared with the mobility of conventional (unstrained) Si p-MOSFET's. Two-dimensional quantization of the holes is taken into account in terms of a self-consistent six-band k . p mod el for the strained band structure and the confined hole subband state s in the inversion channel. The hole dynamics along the inversion chan nel is studied in terms of ensemble Monte Carlo calculations that take into account all relevant scattering mechanisms. For a Ge concentrati on of 30% in the substrate, we predict a mobility enhancement of a fac tor of 2.3 compared to the unstrained p-type device. The calculated lo w-field mobility is in excellent agreement with experimental data for strained Si/Si0.8Ge0.2 and for unstrained Si p-MOSFET's. [S0163-1829(9 8)10635-5].