Properties of molecular-beam-epitaxy-grown and O+-implanted GaAs and their application to the formation of a buried collector of an AlGaAs/GaAs heterojunction bipolar transistor

Changes in properties of molecular-beam-epitaxy-grown GaAs by oxygen-ion (O+) implantation and annealing, such as crystallinity, carrier concentration, and sheet resistance, are investigated. Using these results, we developed a method of O+ implantation through an external base area to form a small buried collector and to minimize the product, R/sub b/C/sub bc/, of the base-collector capacitance C/sub bc/ and the base resistance R/sub b/ in an AlGaAsGaAs heterojunction bipolar resistance R/sub b/ in an AlGaAsGaAs heterojunction bipolar transistor (HBT) fabricated by a multiple self-alignment process with one mask. High-frequency properties of HBT's are improved by this method remarkably