A Study of Evaporated Thin-Film Devices

Abstract

<p> The deposition parameters of thin vacuum-evaporated films were studied in the development of thin-film devices. These devices, including resistors, diodes and transistors, were constructed by the use of vacuum deposition techniques and metal masks for pattern generation.</p> <p> Stable thin-film resistors were fabricated using nichrome as the resistance material. The variation of resistance value with both temperature and time was investigated.</p> <p> A metal-cadmium sulphide-metal structure was employed as a thin-film diode, the electrodes being of aluminium or gold. The electrical evaluation of such a device demonstrated the importance of the deposition of the semiconductor on the rectifying properties. Forward to reverse resistance ratios of 10^5 were observed for experimental units.</p> <p> The staggered-electrode structure was incorporated in the production of thin-film transistors. Cadmium sulphide was used as the semiconducting material while silicon monoxide and aluminium were used as the insulator and electrodes respectively. Operating devices exhibiting good saturation characteristics has transconductances of 450μ mhos. Simple circuits were constructed to demonstrate the performance of thin-film transistors. (</p>