| 摘要 |
PURPOSE:To prevent a metal residue by a method wherein, after a poly Si film is grown, an impurity is ion-implantated with an obliquity of at least 45 deg. or more and the poly Si film is etched by a wet etching method. CONSTITUTION:An oxide film 2 and a nitriding film 3 are formed on a base 1 and thereafter, a non-doped poly Si film 7 is deposited on the surfaces. Then, such an impurity as boron is ion-implantated 8 with an oblique angle of at least 45 deg. or more. The doped poly Si film 7 is subjected to wet etching. Then, arsenic or the like is ion-implantated on the emitter side using a photo resist 10 as a mask and boron or the like is similarly ion-implantated on the base side to form contact regions 12. Since the thickness of the poly Si film can be made smaller than the step difference between the films 2 and 3, this device is never made in such a construction that a metal is left.
|
