SELF-LIMITING ETCH PROCESS FOR REFRACTORY CONTACTS TO GaAs DEVICES
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Disclosed is a dry etching process for refractory contact metals, such as Ni, Pt, Pd and Mn with acceptable selectivity over GaAs or bilayered GaAs/AlGaAs substrates. These refractory metal films cannot be delineated by a conventional reactive ion etching method using halogen gas plasmas, limiting a choice of refractory metals for electrical contacts of GaAs devices. The present technique opens up this limitation by combining a physical sputtering of refractory metals by Ar plasma and a polymer deposition on GaAs by hydrocarbon or fluorocarbon gas plasmas, such as C2H4 and C2F6 . In a conventional reactive ion etching reactor configuration, argon ions contribute mostly to physical sputtering, while hydrocarbon radicals tend to form a passivation layer on the surface.