Dielectrically Isolated Thick Si Films by Lateral Epitaxy from the Melt

Abstract

Dielectric isolation (DI) technology has been available for almost 20 years. It was first developed for low capacitance, high speed circuits, and was later adapted to radiation‐hardened devices and for high voltage isolation. The conventional DI technology is expensive, and device yields are reduced by mechanical instability of the polycrystalline substrates. We review a novel approach to forming DI structures, based on recrystallization from the melt of thick Si films deposited over oxidized Si wafers, with a regular array of seeding windows opened in the isolation oxide. The recrystallized films are free of grain boundaries and subboundaries and contain few dislocations. Most important, the polycrystalline substrates and the associated wafer bow are eliminated.