A semiconductor device includes a bipolar junction transistor (BJT) structure including emitters in a first well having a first conductive type, collectors in respective second wells, the second wells having a second conductive type different from the first conductive type and being spaced apart from each other with the first well therebetween, and bases in the first well and between the emitters and the collectors. The BJT structure includes active regions having different widths that form the emitters, the collectors, and the bases.

A three terminal high voltage Darlington bipolar transistor power switching device includes two high voltage bipolar transistors, with collectors connected together serving as the collector terminal. The base of the first high voltage bipolar transistor serves as the base terminal. The emitter of the first high voltage bipolar transistor connects to the base of the second high voltage bipolar transistor (inner base), and the emitter of the second high voltage bipolar transistor serves as the emitter terminal. A diode has its anode connected to the inner base (emitter of the first high voltage bipolar transistor, or base of the second high voltage bipolar transistor), and its cathode connected to the base terminal. Similarly, a three terminal hybrid MOSFET/bipolar high voltage switching device can be formed by replacing the first high voltage bipolar transistor of the previous switching device by a high voltage MOSFET.

A device and methods of forming the same are described. The device includes a substrate and a first bipolar junction transistor (BJT) disposed over the substrate. The first BJT includes a first base region, a first emitter region, and a first collector region. The device further includes a second BJT disposed over the substrate adjacent the first BJT, and the second BJT includes a second base region, a second emitter region, and a second collector region. The device further includes an interconnect structure disposed over the first and second BJTs, and the interconnect structure includes a first conductive line electrically connected to the first emitter region and the second base region and a second conductive line electrically connected to the first collector region and the second collector region.