Fiber-optics coupled detector arrays using thin film cadmium sulfide Schottky diodes

Epitaxial films of cadmium sulfide grown on silicon and on germanium are used as the basis for Pt-CdS photovoltaic Schottky diodes. The CdS films are vacuum deposited using a resistance heated source and an alumina crucible. The rate of deposition is approximately 300 Angstroms per minute, and the substrate temperature during deposition is 275°C. The platinum films are deposited from a second, tungsten, resistance heated source at a rate of about 7 Angstroms per minute. The thicknesses of the CdS and Pt films are typically 1 micron and 40 Angstroms, respectively. Electrical contact to the platinum electrode is made by thermocompression bonding gold wire to an aluminum pad deposited on the platinum.