Characterization of WNx/GaAs Schottky Contacts Formed by Reactive RF Sputtering

Abstract

The structural and electrical characterization of WNx/GaAs Schottky contacts formed by a reactive rf sputtering in a mixed nitrogen-argon gas atmosphere was performed under various fabricating conditions to establish a Schottky gate for a self-aligned GaAs MESFET. The characteristics of a WNx film and a WNx/GaAs contact greatly depend on the relative nitrogen gas partial pressure γ, rf sputtering power P0, and annealing temperature TA. We determined the optimum values of γ, P0, and TA in order to obtain an excellent thermally stable WNx/GaAs Schottky contact for a self-aligned gate, with a typical barrier height φBOI of about 0.94 eV and an ideality factor n of ∼1.1.