A method for producing vertical bipolar transistors having different
voltage breakdown and high-frequency performance characteristics on a
single die comprises forming, for each of the vertical bipolar
transistors, a buried collector region, and base and emitter regions
above the buried collector region. The lateral extensions and locations
of the base and emitter regions and of the buried collector region are,
for each of the vertical bipolar transistors, selected to create an
overlap between the base and emitter regions, and the buried collector
region, as seen from above, wherein at least some of the overlaps are
selected to be different.