Tadashi Kiriseko

Method for producing a bipolar transistor utilizing an oxidized semiconductor masking layer in conjunction with an anti-oxidation mask

A method for producing a bipolar transistor which has no emitter-base short and which attains a high density of integration. The method comprises the steps of forming a polycrystalline silicon layer on an anti-oxidation masking layer formed on a base region, selectively etching the polycrystalline silicon layer to form an opening, introducing impurities into the base region to form an emitter region, converting the polycrystalline silicon layer into an oxide layer whereby the size of the opening is reduced, selectively etching the anti-oxidation masking layer to form an emitter electrode opening, and forming electrodes.