High Current Gains Obtained by InGaN/GaN Double Heterojunction Bipolar Transistors

Abstract

InGaN/GaN double heterojunction bipolar Npn transistors have been fabricated using p-type InGaN and n-type GaN as base and collector layers, respectively. The structures were grown on SiC substrates by low-pressure metalorganic vapor phase epitaxy. The In mole fraction in the base layer and its thickness were 0.06 and 100 nm, respectively. The Mg doping concentration in the base layer was 1 x 10 19 cm -3 corresponding to a hole concentration of 5 x 10 18 cm -3 at room temperature. The common-emitter I-V characteristics showed good saturation characteristics and a maximum current gain of 20 was obtained at room temperature.