| 摘要 |
A method for making a heterojunction bipolar transistor in which the collector (46) is epitaxially grown on the subcollector layer (36) through a hole (42) formed in a layer of insulating material (40) deposited on the subcollector layer (36). A base (48) is epitaxially grown on the collector (46). Because of unequal lateral and vertical growth rates, the peripheral region of the base extends over the layer of insulating material. The n and n+ layers (50, 52) of the second type of semiconducting material are sequentially grown on the base and an n+ layer (54) of the first type of semiconducting material is grown on the sequentially grown layers (50, 52). The n+ layer (54) and the sequentially grown layer (50, 52) are etched to form an emitter mesa over the collector (46) leaving exposed the peripheral portion of the base (48) extending over the layer of insulating material surrounding the hole (42). Metallic electrodes (62, 64 and 68) are then deposited which electrically contact the base (48), the emitter (54) and the subcollector (36).
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