Adhesion improvement of Au on GaAs using ion beam assisted deposition

Ion beam assisted deposition (IBAD) has been applied to create strongly adhering Au-GaAs interfaces at low temperatures (120-150degC), which display excellent Schottky barrier height and ideality factor. The interface thus created is believed to involve Au-Ga bonding, and its extent is limited to a depth of a few monolayers. The adhesion produced depends critically on substrate temperature and on the arrival rate ratio of Ar ions to Au atoms at the substrate. The mechanism of the interface complex formation is not yet determined; however, it is postulated that surface disorder created by the ion beam contributes critically to enabling the chemical displacement of As by Au at the GaAs surface. (orig.)