Vol. 39, Issue 4, pp. 787-797 (2009)

Abstract

The effects of HCl-based chemical and Ar⁺ sputter etching treatment on (100) GaAs surface properties with the aim to develop the procedure of surface preparation before metal deposition have been investigated. Variable angle spectroscopic ellipsometry, X-ray photoelectron spectroscopy, atomic force microscopy and photoluminescence have been used to study the surface characterization. We show that combining chemical etching in 5% HCl with Ar⁺ sputter etching gives the best results for surface cleaning prior to metal deposition. The application of this two-step treatment allows to obtain Ni/AuGe/Ni/Au ohmic contact with r_c = 2×10^–6 Ωcm² with excellent adhesion and long-term thermal stability.