Amorphous Silicon-Germanium-Boron Alloy Applied to Low-Loss and High-Speed Diodes

Abstract

Properties of chemically vapor-deposited amorphous silicon-germanium-boron alloy are reported with special reference to its applicability to contact electrodes in silicon device technology. Contact properties of the amorphous alloy with p on n⁺ and n on n⁺ epitaxial single-crystalline silicon are investigated. The forward on-voltage and reverse recovery time of these diodes decrease drastically in comparison with those of corresponding conventional p-n and Schottky structures. On account of its dense localized states, the amorphous alloy can be regarded as a Schottky metal providing a low barrier height for holes. This enables the low-loss and high-speed operation of these diodes, the mechanism of which is discussed here. The effective work function of this amorphous alloy is also estimated.