Inversion-type enhancement-mode HfO2-based GaAs metal-oxide-semiconductor field effect transistors with a thin Ge layer

Using a thin germanium (Ge) interfacial passivation layer (IPL), GaAs HfO2-based inversion-type enhancement-mode metal-oxide-semiconductor field effect transistors (MOSFETs) are realized. The n-channel MOSFETs on semi-insulating GaAs substrate clearly show surface modulation and excellent current control by gate bias. The threshold voltage of similar to 0.5 V, the transconductance of similar to 0.25 mS/mm, the subthreshold swing of similar to 130 mV/decade, and the drain current of similar to 162 mu A/mm (normalized to the gate length of 1 mu m) at V-d=2 V and V-g=V-th+2 V are obtained. In comparison with previous reports, the dc characteristics of the inversion-type GaAs MOSFETs with a Ge IPL and HfO2 dielectric demonstrate much similar results. (c) 2008 American Institute of Physics.