Undoped SiGe FETs with metal-insulator-semiconductor contacts

With relaxed SiGe, this work elaborates the correlation of semiconductor band edges and source-drain metal workfunction for the electrical characteristics of p- and n-channel FETs based on numerical simulations. For a given high workfunction source-drain metal, it is found that the on-current, threshold voltage and off-current of p-channel devices increase monotonously with the Ge mole fraction. The trend of the n-channel devices, however, seems more complicated, but it can be interpreted by the band edge variation of SiGe alloy.