High current gains obtained by InGaN/GaN double heterojunction bipolar transistors with p-InGaN base

InGaN/GaN double heterojunction bipolar transistors have been fabricated using p-type InGaN as a base layer. The structures were grown on SiC substrates by metalorganic vapor phase expitaxy and defined by electron cyclotron resonance plasma etching. 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 1×10¹⁹ cm^-3 corresponding to a hole concentration of 5×10¹⁸ cm^-3 at room temperature. From their common-emitter current–voltage characteristics, the maximum current gain of 20 was obtained at room temperature. © 2001 American Institute of Physics.