Front and back side processed unintentionally doped GaAs Schottky detectors for X-ray detection

We have studied the current voltage and X-ray detection using front and back side processed, unintentionally doped bulk GaAs Schottky detectors. GaAs detectors with large enough thickness and low enough doping could be used for X-ray imaging, especially for medical applications. GaAs Schottky detectors were fabricated using front and back side photolithographic processing with Ti/Au for Schottky and Ge/Au/Ni/Au for Ohmic contacts. A number of detectors of size 2 mm 2 were tested. The breakdown voltage reached 600- 800 V in semi insulated (SI) GaAs Schottky front and back side processed detectors. For these detectors the dark current was found to be between 2- 90 nA. These detectors were also characterized with 150 keV, 3mA X-ray radiation and they responded well by showing more than a hundred fold increase in photocurrent due to production of electron hole pairs by the ionization processes. The processing of the detectors and the I-V and X-ray characterization is presented in this report.