| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of leakage current being generated in a bipolar transistor, due to crystal defect produced during the formation of an embedded layer through ion implantation of impurity, and the transistor characteristic being deteriorated as a result. SOLUTION: In this bipolar transistor, the impurity concentration of a collector forming region in an embedded collector layer is made lower than that of a collector electrode region therein, reducing crystal defects that are produced due to excess impurities in the collector formation area. Continuingly, crystallinity of continuously formed P (phosphorus)-doped epitaxial Si layer, epitaxial SiGe alloy layer, and Si epitaxial film is also made superior, and leakage current will not occur and high reliability can be obtained.
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