HETERO-JUNCTION BIPOLAR TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To enhance a current amplification factorβand the element reliability still more. SOLUTION: A sub-collector layer 9, an n-GaAs collector layer 3, a p-GaAs base layer 4, an n-InGaP or n-AlGaAs emitter layer 5, an n-GaAs emitter cap layer 6, an n-InGaAs graded emitter cap layer 7 and an n-InGaAs emitter cap layer 8 are sequentially formed on a GaAs substrate 1 to constitute a hetero-junction bipolar transistor. With this arrangement, the sub-collector layer 9 is formed of n-InGaP. A range of an In mixed crystal rate of this n-InGaP sub-collector layer 9 is 0.4 to 0.6, and a carrier density thereof is 1×1018to 1×1019cm-3, preferably. COPYRIGHT: (C)2005,JPO&NCIPI