| 摘要 |
PURPOSE:To form a graft base layer and an active base layer simply through one-time diffusion process by shaping an silicon compound coating at the stepped section of a diffusion window opened on an insulating film on the main surface of a substrate and executing ion implantation treatment and diffusion treatment. CONSTITUTION:An N-type buried layer 2, an N-type epitaxial layer 3 and a P-type isolation diffusion layer 4 are formed onto a P-type Si substance 1, an SiO2 film 10 is grown, and a diffusion window is bored. An Si compound applying coating 12 is applied, and removed left only to a section in the vicinity of the stepped section of the window, and the ions of boron as a diffusion impurity are implanted. Boron is diffused through a thermal diffusion method, etc. to simultaneously shape an active base layer 6a and graft base layers 5a. An opening (not shown) is formed to a required section in the SiO2 film 10, and phosphorus is diffused to shape an N-type emitter layer and an N-type collector contact layer (both are not shown), thus acquiring a semiconductor device having graft base structure.
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