VLSI Technology

Abstract

VLSI (Very Large Scale Integration) is responsible for the very complex, yet low-priced, integrated circuits (ICs) that are available today. It is the continuation of a process which began in the mid-1960s when the first ICs began to appear. These circuits employed silicon as the active medium rather than germanium, which had been commonly used for solid-state devices up to 1960. Silicon dioxide was the key feature of this technology: it was readily produced by thermal oxidation of the silicon substrate, it was highly adherent, was insoluble in water (unlike germanium dioxide), was impenetrable by dopants and could be selectively etched with hydrofluoric acid (HF) to form windows for diffusion.