Abstract

Radiation detectors work as Schottky devices. The Schottky contact of the investigated detectors consists of a Ti/Pt/Au layer on the front-side of a 500?m thick semi-insulating GaAs substrate. The back-side is an alloyed Ge/Au ohmic contact.The structure of these contacts are squares with sides of between 1,5mm and 5mm. In order to seperate the behaviour of the contacts, an independent determination of those parameters of the bulk material which are responsible for a satisfactory functioning of the detector are necessary. We present a theoretical model of the detector which simulates detector properties according to relevant parameters such as the resistivity p, the mobility ? of the charge carriers, the energy level EDD and concentration NDD of the bulk-defects and the leakage-current jL of the device. The aim of this study is to determine these parameters experimentally and compare materials from different suppliers. The relevant parameters are then used for the detector simulation.