Patent ID: 7927955
Filing Date: 2011-04-19
Classification: H01L

Abstract:
1. A method for forming a bipolar semiconductor device employing a MOS device process having a first conductivity well forming step and a shallow second, opposite, conductivity type contact region forming step, the method comprising: providing a semiconductor substrate having a first surface; providing one or more first partial blocking mask portions on the first surface above a location where an emitter region will subsequently be formed, wherein openings to the first surface are present between the one or more first partial blocking mask portions; providing an implant through the openings to form a base region of the bipolar semiconductor device having a first conductivity type, wherein the one or more first partial blocking mask portions inhibit implantation below the one or more first partial blocking mask portions, resulting in the base region having an undulating lower boundary at least partially defined by one or more hump regions nearer the first surface and in one or more locations that correspond to locations directly underlying the one or more first partial blocking mask portions; and forming the emitter region in the base region proximate the first surface, wherein the emitter region is adapted to function in cooperation with the hump regions.