| 摘要 |
PROBLEM TO BE SOLVED: To provide a heterojunction type bipolar transistor which has little variations in a base mesa step and is capable of improving yield. SOLUTION: This transistor is constituted by stacking an emitter layer 105, which comprises an n<+> -GaAs subcollector layer 102, an n-GaAs collector layer 103, a P<+> -GaAs based layer 104 and an n-InGaP, and a cap layer 106. In this case, a Si-doped n-Inx Ga1-x P layer 110 (mixed crystal ratio of In: x=0.474, Si doping concentration: 1×10<18> cm<-3> ), which is to become an etching stopper layer, having a film thickness of 10 nm, is inserted between the subcollector layer 102 and the collector layer 103.
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