Low temperature mobility in hafnium-oxide gated germanium p -channel metal-oxide-semiconductor field-effect transistors

Abstract

Effective mobility measurements have been made at 4.2 K on high performance high- k gated germanium p -type metal-oxide-semiconductor field effect transistors with a range of Ge/gate dielectric interface state densities. The mobility is successfully modelled by assuming surface roughness and interface charge scattering at the Si O2 interlayer/Ge interface. The deduced interface charge density is approximately equal to the values obtained from the threshold voltage and subthreshold slope measurements on each device. A hydrogen anneal reduces both the interface state density and the surface root mean square roughness by 20%. © 2007 American Institute of Physics.