| 摘要 |
PURPOSE: To reduce emitter/base leakage and capacitance by providing a layer which includes an emitter/base hetero-junction, having a predetermined concentration profile made of at least one band-gap determining material and which has a specified transistor structure. CONSTITUTION: A base aperture 17 is formed at a position between an isolation trench 11 and an N<+> reach-through region 14. Next, a P<+> SiGe blanket layer 18 to be an intrinsic base and a non-doped Si layer 19 to be an emitter are formed. It is preferred that the P<+> SiGe blanket layer 18 doped at a high concentration be made extremely thin, with a thickness of approximately 30 nm in the base aperture 17. It is also preferable that the P<+> SiGe blanket layer 18 and the non-doped Si layer 19 be formed by a single low-temperature epitaxy method, with the concentration of a dopant and an alloy material being varied. Therefore, these layers can be considered as a single layer. Thus, emitter/base leakage and capacitance can be reduced.
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