Bipolar transistor with reduced vertical collector resistance

摘要

High energy implantation through varying vertical thicknesses of one or more films is used to form a vertically modulated sub-collector, which simultaneously reduces both the vertical and lateral components of parasitic collector resistance in a vertically integrated bipolar device. The need for a sinker implant or other additional steps to reduce collector resistance is avoided. The necessary processing modifications may be readily integrated into conventional bipolar or BiCMOS process flows.