EPITAXIAL WAFER FOR HETEROJUNCTION BIPOLAR TRANSISTORS, AND HETEROJUNCTION BIPOLAR TRANSISTOR ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide an epitaxial wafer for heterojunction bipolar transistors and a heterojunction bipolar transistor element which enable the increase in current gain while minimizing a turn-on voltage.;SOLUTION: An epitaxial wafer 100 for heterojunction bipolar transistors comprises: a base layer 105 made of In_yGa_1-yAs(0y≤0.10); a collector layer 103; an energy barrier-reduction layer 104 made of In_x→0Ga_1-x→1As(0x≤0.10), where the composition of In decreases from the base layer 105 toward the collector layer 103, of which the thickness is less than 30 nm; and an emitter layer 106 made of In_zGa_1-zP(0.48≤z≤0.58). The total layer thickness of the energy barrier-reduction layer 104, the base layer 105, and the emitter layer 106 is 100 nm or less.;COPYRIGHT: (C)2015,JPO&INPIT