FOUR RADICAL COLLECTOR INALAS-INGAALAS HETEROJUNCTION BIPOLAR TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To increase a base transition time by a method wherein a grade emitter base transition region of a grade composition is formed between an emitter and a base. SOLUTION: An n-type InGaAlAs grade emitter base transition layer 28 which is doped to about 5×10<17> atoms/cm<3> is formed to a thickness of about 45 nm on a base layer 24. The grade layer 28 forms an In0.53 Ga0.37 Al0.10 As composition of substantially the same composition as the base layer 24 in an interface between the grade layer 28 and the base layer 24. Further, the grade layer 28 has a composition of In0.52 Ga0.01 Al0.47 As of substantially the same composition as an emitter layer 30 in an interface between the grade layer 28 and the emitter layer 30. The base layer 24 is replaced with a grade doped p-type InGaAs layer or the grade composition InGaAlAs base layer. Thereby, a high base transition time can be obtained.