Uniform current density and high current gain bipolar transistor

摘要

A bipolar transistor designed to support a substantially uniform current density in base and collector regions to prevent the characteristic early fall-off of bipolar transistor current gain, and to improve the forward safe operating area performance. The advantages of the present invention are achieved by optimally spacing the neighboring emitters in relation to base thickness and further by maintaining a symmetrical topology by the self-aligned formation of emitters and base contacts. The spacing distance between the neighboring emitters does not exceed the base thickness. As a result, the current density below each emitter island is substantially uniform and the transistor as a whole can conduct a higher total current. Moreover, the transistor inhibits formation of current filaments and hot spots because the electric field in the collector region is uniform.