Low Temperature Atmospheric Pressure Chemical Vapor Deposition for Epitaxial Growth of SiGe Bipolar Transistors

Abstract

Atmospheric pressure chemical vapor deposition (APCVD) has been used to grow an epitaxial SiGe-base for a novel self-aligned low thermal budget heterojunction bipolar transistor (HBT) device. The hydrogen growth ambient is shown to greatly facilitate the growth of high quality epitaxial layers in the range 550 to 750°C. SiGe was deposited from silane, germane, and diborane using gas switching. Convenient growth rates were achieved with SiGe alloy compositions of 10 to 30% Ge and 1017 to 1019/cm3 p-type doping. The SiGe-base region was a.box-shaped profile about 60 nm wide with a narrow boron spike nested inside. The Gummel characteristics of transistors were ideal indicating high quality material, and the devices had excellent ac characteristics which have been reported elsewhere. © 1995, The Electrochemical Society, Inc. All rights reserved.