| 摘要 |
PURPOSE:To give a process allowance by a method wherein an impurity is introduced through an SiO2 film, an emitter region is formed while the SiO2 film is changed into an impurity glass layer, the glass layer on the emitter region is removed and the whole is thermally treated when forming transistors having different junction depth. CONSTITUTION:N type collector regions 12, N<+> type collector buried regions 14, a P type isolation region 19, thick SiO2 films 15, thin SiO2 films 16a, 16a', 16c, 16c', 16d, Si3N4 films 17 and 18, and P type base regions 13 are formed to a P type Si substrate 11 through a normal method. The films 16a', 16c', 17, 18 are removed selectively through etching, and thick SiO2 films 15a are formed through selective oxidation. The films 16a', 16c', 16b, 16d, 17, 18 in the surface are removed selectively, and an N type impurity is diffused through the films 16a, 16c to shape N<+> type emitter regions 20, 21 and collector electrode leading- out regions 22, 23 while a surface layer is changed into a PSG film 24. The PSG film 24 is removed selectively, and regions 20 and 21 in different depth are obtained through heat treatment. |
