A bipolar transistor is provided which includes a tapered, i.e. frustum-shaped, collector pedestal having an upper substantially planar surface, a lower surface, and a slanted sidewall extending between the upper surface and the lower surface, the upper surface having substantially less area than the...http://www.google.com.au/patents/US7425754?utm_source=gb-gplus-sharePatent US7425754 - Structure and method of self-aligned bipolar transistor having tapered collector
