6 - Semiconductor, Thick and Thin-Film Microcircuits

Abstract

Silicon is unrivalled as a semiconductor material for active devices such as rectifiers, metal oxide semiconductor field effect transistors (MOSFETS), bipolar transistors, thyristors, and a wide variety of other structures particularly designed for power applications. Few of the properties of silicon are ideal but none are so far from ideal as to exclude its use in all but a small fraction of current devices. Hybrid microcircuits use patterns of thick and thin conducting films on an inert substrate to replace individual resistors, and to connect components such as capacitors, transistors and integrated circuits (ICs) into a complete circuit, thus saving space and weight compared with printed circuit boards (PCBs). The first application of microcircuit techniques was for the wartime production of proximity fuses, using printed carbon composition resistors on ceramic substrates. Since then, the materials used for hybrids of thick- and thin-film materials are being continually up-graded and extended, to improve the final product.