Fabrication and Electrical Characterization of SI/SIGE P-Channel MOSFETs with a Delta Doped Boron Layer

CVD epitaxy which has been used for channel engineering of 300 nm MOSFETs offers besides delta doping the attractive feature to implement a Si/SiGe/Si quantum well with higher mobility of the charge carriers. For the p-channel transistor this SiGe layer can be grown directly on Si substrate. With a content of 15% Ge a step of 150mV is achieved in the valence band where the holes are confined up to gate voltages of about 2V. Low field hole mobilities are improved by 50% in transistors with thin gate oxides resulting in an increase of the saturation current by 20%.