Dry etching device quality high-κ Ga xGd yO z gate oxide in SiCl 4 chemistry for low resistance ohmic contact realisation in fabricating III–V MOSFETs

Abstract

This paper investigates the reactive ion etching (RIE) of Ga x Gd y O z , a device quality high-κ gate oxide for a low resistance ohmic contact realisation in fabricating 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 Oxford Instrument PlasmaLab System 100 RIE etcher with a SiCl 4 based chemistry. The GGO high-κ gate stacks for GaAs MOSFETs were grown by Molecular Beam Epitaxy (MBE) in a dual-chamber system. Etching profile was characterised by AFM, SEM and TEM methods. The effects of usual etching conditions, such as RF power and chamber pressure on etch process were investigated. Based on the etching process, a low resistance ohmic contact has been realised as well, which has successfully been used in the fabrication of GaAs MOSFETs.