Inversion mode n-channel GaAs field effect transistor with high-k/metal gate

Abstract

Highly effective passivation of GaAs surface is achieved by a thin amorphous Si $\left(a\text{-}\mathrm{Si}\right)$ cap, deposited by plasma enhanced chemical vapor deposition method. Capacitance voltage measurements show that carrier accumulation or inversion layer is readily formed in response to an applied electrical field when GaAs is passivated with $a\text{-}\mathrm{Si}$ . High performance inversion mode $n$ -channel GaAs metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated with an $a\text{-}\mathrm{Si}$ /high-$k$ /metal gate stack. Drain current in saturation region of $220\mathrm{mA}∕\mathrm{mm}$ with a mobility of $885{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ were obtained at a gate overdrive voltage of $3.25\mathrm{V}$ in MOSFETs with $5\mu \mathrm{m}$ gate length.