| 摘要 |
Devices and methods are disclosed related to a bipolar transistor device and methods of fabrication. A top region is formed at a surface of and within a base region. The top region is formed by implanting a dopant of an opposite conductivity to that of the base region. However, the top region remains of the same conductivity type as the base region (e.g., n-type or p-type). This implanting, also referred to as counterdoping, increases resistivity of the top region and thus improves an emitter-base breakdown voltage. Additionally, this implanting does not have a substantial detrimental affect on a beta value, also referred to as an amplification property, or a collector emitter breakdown voltage, also referred to as BVceo, for the transistor. The beta value and the collector emitter breakdown voltage are mainly a function of a bottom portion of the base region.
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