| abstract |
Some embodiments are directed to a bipolar junction transistor (BJT) with a collector region formed within a body of a semiconductor substrate, and an emitter region arranged over an upper surface of the semiconductor substrate. The BJT includes a base region arranged over the upper surface of the semiconductor substrate, which vertically separates the emitter and collector regions. The base region is arranged within, and in contact with, a conductive base layer, which delivers current to the base region. The base region includes a planar bottom surface, which increases contact area between the base region and the semiconductor substrate, thus decreasing resistance at the collector/base junction, over some conventional approaches. The base region can also include substantially vertical sidewalls, which increases contact area between the base region and the conductive base layer, thus improving current delivery to the base region. |