Optimization of process parameters for amorphous semiconductor contacts on high-purity germanium detectors

High-purity germanium (HPGe) represents a premium material for gamma-ray spectroscopy and imaging, with electrical contacts playing a large role in detector performance. Amorphous semiconductor contacts to HPGe detectors have been demonstrated to operate as a sufficient charge injection barrier, while providing a simple fabrication process and flexibility in contact geometry and bias application. The primary remaining challenges are reliable reproduction of high barrier heights and inter-contact impedance as well as stability with respect to time and temperature cycling. The results from a study of electron barrier height and temperature cycling stability with varying process conditions are given in this paper.