Surtace Science 168 (1986) 301-308 North-Holland. Amsterdam THE FORMATION OF THE Au-GaAs(001) INTERFACE Thorwald G ANDERSSON, Janusz KANSKI, Guy LE LAY* and Stefan P SVENSSON Department of Phwtc~, Chalmer~ Untvers:tv of Technology, S 412 96 Goteborg, Sweden Recewed 10 June 1985, accepted for pubhcatlon 20 June 1985 The lormatlon of the Au-GaAs(001) interlace ~s studied by electron spectroscopy and elec- tron diffraction Sample surface and overlayers are prepared by molecular beam epltaxy Depo- smon at room temperature converts the c(2×8) reconstruction to d~sorder at 1 A The overlayer growth Is laminar and crystalhne gold m epltaxy with the substrate Is observed at 4 ~ Growth at 30/)°C is laminar only mltmlly since domam growth starts at 0 5 A At higher growth temper- atures the Auger signal increases very slowly with deposition reflecting both mterd~ffus~on and clustermg Anneahng of a room-temperature grown submonolayer shows a strong substrate interaction at 300°C where also the surface content of galhum increases 1. Introduction Detaded understanding of the metal-GaAs interface ~s highly desirable, both for fundamental physical reasons and due to lncreasmgly sophisticated applications [1] Such examples are Schottky diodes in high-frequency devices and small-area ohmic contacts for high current densities Several characteris- tics of the contact, such as Fermi-level pinning and development of the metal- lic surface occurs m the monolayer (ML) range Therefore study of the forma- tion process of the contact is an ~mportant ingredient m the puzzle leading to a physical understanding of the contact In this paper we present a compre- hensive analysis of the ML-development of the Au/GaAs(001) system The growth process is followed in close relatzon to the evolution ot the surface electromc structure The present paper is part of an extensive study of the Au-GaAs(001) system, including Au coverages from sub-ML to ~-I00 A, growth at elevated temperatures and anneahng expertments Most of the earher work concernmg Au/GaAs mterface formation has been performed on the cleaved GaAs(ll0) surface These studies revealed strong adsorbate-substrate interaction resulting m non-laminar growth [2] and Fermi-level pinning m the sub-ML range [3,4] The gold Fermi level was * CRMC2-CNRS, Campus de Lummy, Case 913, 13288 Marsedle Cedex ll9 France 0039-6028/86/$03 50 © Elsevier Science Pubhshers B V (North-Holland Physics Pubhshmg Division)