| 摘要 |
PURPOSE:To perform three diffusions with excellent controllability and reproducibility, by performing the first diffusion through windows in an insulating film via a semiconductor film, performing the second diffusion through windows in the oxide film converted from the semiconductor film via a new semiconductor film, and similarly performing the third diffusion. CONSTITUTION:An Si polycrystalline layer 23 is formed on an SiO2 film 21 having holes 22 and 22' on a P type Si substrate 1. A resist film 24 having a hole at the part of the layer 23 is formed. Thereafter phosphorus impurities are implanted, annealing is performed, and an N type collector region 25 is formed. An Si3N4 film 26 is deposited on the entire surface of the substrate 27. Holes 27 and 27' are provided. With said film 26 as a mask, the parts exposed by the hole 27 and 27' are converted into SiO2 films 28 and 28'. The Si3N4 film 26 is removed, P type impurities are introduced with a resist film 29 as a mask, and a P type base region 30 and a contact region 31 are formed. An emitter region 35 is similarly formed. Thus the three diffusions are performed with excellent controllability and reproducibility. |
