High Quality Silicon Epitaxy In An Ultra High Vacuum Rapid Thermal Cvd Reactor: An Application to Single Wafer Processing

Abstract

ABSTRACTIn this paper, we report epitaxial growth of silicon in an ultra high vacuum rapid thermal chemical vapor deposition (UHV/RTCVD) equipment. In this study, our objectives were low temperature/low thermal budget processing and a high throughput compatible with single wafer manufacturing. The reactor consists of a load lock, a main process chamber and an intermediate cryopumped vacuum buffer chamber between the two chambers. An ultra-clean process environment was achieved using oil free pumps and point of use gas purifiers. The wafer is heated by a Peak Systems LXU-35 arc lamp through a quartz window. In this system, we achieved good quality silicon epitaxy at low temperature (T≤800°C) in the very low, 100 mTorr, pressure regime with high throughput (Growth rate>0.25 μm/min.). High growth rate was achieved using Si2H6 as the reactant gas instead of SiH4 or SiH2C12 which are more commonly used gases for epitaxial growth. High temperature in-situ cleaning was completely eliminated by initiating film growth on a hydrogen passivated surface obtained via dilute HF etching. Generation lifetimes in the 200-400μs range were measured for deposition temperatures of 700°C, 750°C and 800°C with no strong dependence on the deposition temperature.