Dry etching of a device quality high-k Ga xGd yO z gate oxide in CH 4/H 2–O 2 chemistry for the fabrication of III–V MOSFETs

Abstract

This paper investigates the reactive ion etching of Ga x Gd y O z , a device quality high-k gate oxide for the fabrication of III–V metal-oxide-semiconductor field-effect-transistors (MOSFETs) based on high mobility channel device layer structures. The etching of Ga x Gd y O z (GGO) was performed in an SRS System ET340 with a CH 4/H 2/O 2 based chemistry The GGO high-k gate stacks for GaAs MOSFETs were grown by molecular beam epitaxy in a dual-chamber system. Etching profile was characterised by SEM using a wet chemical HCl/HF/H 2O decoration etch to assist layer identification. The effects of etching gas, RF power, and duration of CH 4/H 2 and O 2 gas cycles on etch process were investigated.