Patent ID: 6124180
Filing Date: 2000-09-26
Classification: H01L,Y10S

Abstract:
In the fabrication of a BiCMOS integrated circuit where a bipolar transistor is formed in a substrate region of a first conductivity type, the improvement comprising the steps of:forming a base region in said substrate region by implanting ions of a second conductivity type into said first conductivity type substrate region using at least two different energy levels, the lower energy level for implanting said second type conductivity ions into said substrate region so as to form an active base region, the higher energy level for implanting said second conductivity type ions deeper into said substrate region than the lower energy level implant so as to form a more lightly doped first conductivity type substrate region near said base region; andforming an emitter region in said base region over said more lightly doped first conductivity type substrate region.