In this study the influence of low energy hydrocarbon ion irradiation at a glancing angle on electronic propel-ties of the GaAs surface and Al-GaAs interface was investigated. The formation of a thin carbon enriched multiphase layer on the GaAs surface was observed. Despite this, reduction of the low-frequency noise, (especially at low temperatures), and effective barrier height of Schottky contacts were achieved at irradiation doses greater than or equal to 10(15) ion/cm(2). The obtained results are explained by the homogenization of the current flow through the Al-GaAs Schottky contact interface layer. (C) 2003 Elsevier Ltd. All rights reserved.