Temperature dependent minority electron mobilities in strained Si1-xGex (0.2 <= x <= 0.4) layers

Temperature-dependent minority electron mobilities in p-type SiGe have been measured for the first time. Measurements were made on test npn SiGe/Si he terojunction lbipolar transistors (HBT's) with pseudomorphic p-type Si1-xGe x (0.2 less than or equal to z less than or equal to 0.4) base layers, Magn etotransport measurements were performed on the fabricated HBT's to obtain the minority electron mobilities in the heavily B-doped base lavers for tem peratures ranging from 5 to 300 K. The measured minority electron mobilitie s exhibited sharp increase with decreasing temperature, and also showed enh ancement with decreasing base Ge composition, The cut-off frequency techniq ue was also employed to estimate the room temperature minority electron mob ilities of the alloys and the results confirmed the trend in mobilities wit h Ge composition as determined by the magnetotransport technique.