Investigation Of Power Mosfet With Strained Sige Channel

Two trench-gated power MOSFETs using strained SiGe channel are proposed to further reduce specific on-state resistance. The first is a multiple SiGe and Si layer structure for N-channel MOSFET. A 30nm Si0.85Ge0.15 layer and a 50nm Silicon layer are grown by RPCVD alternatively to achieve sufficient channel length which is longer than the critical thickness before the trench etch. The second method is to form the strained SiGe layer along the trench sidewall for P-channel MOSFET. A single Si0.85Ge 0.15 layer of 30nm thick is grown after the trench etch. It is expected that the channel mobility in the vertical direction will be increased by up to 40% and 60% for electrons and holes, respectively, compared to conventional silicon device with same structure and doping profile. The on-state resistance is predicted to be reduced by 12% and 20% for N-channel and P-channel MOSFET accordingly. ©The Electrochemical Society