Superjunction collectors for transistors are discussed in this application. According to one embodiment, a bipolar transistor having a superjunction collector structure can comprise a collector electrode, a base electrode, an emitter electrode, a collector-base space charge region, and a superjunction collector. The collector-base space charge region can be disposed in electrical communication between the collector electrode and the base electrode. The superjunction collector region can be disposed in the collector-base space charge region. The superjunction collector region can comprise a plurality of alternating horizontally disposed P-type and N-type layers. The layers can be horizontally disposed layers that are layered on top of each other. The P-type and N-type layers can be doped with different types of doping levels. Other aspects, embodiments, and features are also discussed and claimed.