Influence of the compensation in semi-insulating GaAs on the particle detector performance

GaAs Schottky diodes made by commercial undoped semi-insulating (SI) material have been shown to work well as radiation detectors. This material offers high radiation resistance together with high charge carrier mobility, good signal-to-noise ratio and a good detection efficiency for minimum ionizing particles. To optimise the detector performance of Schottky diodes made on SI-GaAs, the influence of the compensation on the formation of the space charge region and charge collection efficiency (CCE) for alpha particles was studied. A strong dependence of the CCE on the ionized state of the arsenic antisite defect As/sub Ga//sup +/ and the resistivity determined from the Norde plot was observed. Also the influence of the compensation on the Schottky barrier height and space charge density can been seen.