Low-field hole mobility of strained Si on (100) Si1−<i>x</i>Ge<i>x</i> substrate

Abstract

Strain Hamiltonian and k⋅p theory are employed to calculate low-field hole mobility of strained Si layers on (100)Si1−xGex substrate. Nonparabolicity and the warped nature of the valence bands are included. At room temperature, in-plane hole mobilities of strained Si are found to be 1103 and 2747 cm 2 V−1 s−1 for x equal to 0.1 and 0.2, respectively. These hole mobilities are, respectively, 2.4 and 6 times higher than that of bulk Si. This improvement in the mobility results is mainly due to the large splitting energy between the occupied light-hole band and the empty heavy-hole band and smaller effective mass. The effect of p-type doping on mobility is also presented.