Abstract
In this letter we report for the first time the successful fabrication of bipolar transistors in low-temperature (T<inf>dep</inf> = 745°C) epitaxial silicon deposited by a chemical-vapor-deposition (CVD) technology. The epitaxial layers were deposited by an ultra-low-pressure CVD (U-LPCVD) technique utilizing an optimized in-situ predeposition argon sputter clean. The critical parameter during the sputter clean has been identified as the substrate bias. Bias voltages of – 200 or – 300 V create dislocations that form emitter-collector shunts during the bipolar transistor fabrication process; a bias voltage of – 100 V, however, permits the deposition of essentially defect-free (< 10 dislocations cm<sup>−2</sup> by defect etching) epitaxial films suitable for bipolar transistor fabrication. Copyright © 1987 by The Institute of Electrical and Electronics Engineers, Inc.