High Performance Bipolar Transistor With A Ge EPI Base
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
A thin layer (approximately 2000 Angstrom) of Ge on single crystal Si, when annealed by a pulsed ion beam, regrows as an epitaxial layer. A Si substrate is doped, n-type, and a Ge layer, prior to annealing, is provided with p-type impurities; these regions then form the collector and base regions, respectively, of an npn bipolar transistor. An n/+/ poly layer is then selectively deposited for the emitter region of the resulting device which would provide a heterojunction emitter for the efficient injection of minority carrier electrons into the Ge base. Fabrication technology for masking, isolation and contacting is compatible with the usual technology used in the fabrication of such devices.