| 摘要 |
PURPOSE:To form an extremely shallow emitter-base junction by forming a high-concentration inert base first, shaping a contact region through selective oxidation and forming an active base and an emitter through self-alingment from the same opening section while using the same poly Si as a diffusion source. CONSTITUTION:An silicon nitride film 18 and poly Si 17 are etched while employing a photo-resist film 19 a s a mask. B<+> ions are implanted into an N-type epitaxial layer 4 while using the photo-resist film 19 as a mask again to shape an inert base region 20 between an emitter and a base-contact. The photo-resist film 19 is removed, oxide films 21, 21' re formed through selective oxidation while employing the silicon nitride film 18 as a mask, and the silicon nitride film 18 is removed. B<+> ions are implantd to the whole surface, and an active base layer 22 and the base-contact 22' are shaped while using the poly Si17 as a diffusion source. The base-contact is coated with a photo-resist film 23, As<+> ions are implanted, and an emitter 24 and a collector-contact 24' are shaped while employing the poly Si 17 as the diffusion source. |
