Fabrication of high-performance CdZnTe strip detector arrays

摘要

Abstract: Cadmium zinc telluride (CsZnTe) has been applied as a X-ray and gamma-ray radiation detector due to its large bandgap and high atomic number which gives low leakage current and good absorption efficiency. In addition, the CdZnTe detectors can be operated at room temperature with very good energy resolution and excellent spatial resolution. The main challenges in fabricating a large area CdZnTe strip detector array are the requirements of low leakage current in the individual strips of each detector and the good adhesion of the pad metal to the CdZnTe surface for wire bonding. The Detector Systems Branch at Goddard Space Flight CEnter has successfully fabricated the double sized CdZnTe strip detectors for a 6 $MUL 6 array. The strip detector array has 36 double sided detectors with each detector having 127 strips and a guard ring on each side with a spatial resolution $LS 100 $mu@m. The total area of the array is 60 cm$+2$/ with 762 $MUL 762 strips to give 580,000 pixels - a factor of 100 better than other CdZnTe or scintillator arrays. In this paper, we will present our novel processing for fabricating such high performance strip detectors. The leakage current, interstrip resistance and energy resolution were studied as a function of different etchants/time and post-annealing temperature. The effects of chemical etching and post annealing on the CdZnTe surface and interface property were also discussed. !10