| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel epitaxial wafer for a hetero-junction bipolar transistor and the hetero-junction bipolar transistor that can prevent the leak of a current adjacent to an emitter layer and improve a current gain. SOLUTION: In the epitaxial wafer for the hetero-junction bipolar transistor that is provided with at least a collector layer 4, a base layer 5, an emitter layer 6, and an emitter contact layer 7 on a compound semiconductor substrate 2, the emitter contact layer 7 is doped with carbon at a specified concentration. Thus, recombination adjacent to the emitter layer 6 can be greatly reduced while avoiding the deterioration of a current gain due to the leakage of a current beforehand. COPYRIGHT: (C)2004,JPO
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