Uniformity of epilayer grown by ultrahigh-vacuum chemical vapor deposition

Abstract

In this work, we explored the Ge fraction, layer thickness and dopant concentration uniformity of epilayers grown by an ultrahigh-vacuum chemical vapor deposition system (UHV/CVD). Three epilayers were grown for this study: a single epilayer of SiGe, a heavily boron doped Si epilayer and a Si/SiGe superlattice with p(+) Si cap. The uniformity in a wafer was measured to be less than +/- 1.5%. In addition, we explored the wafer-to-wafer uniformity of a strained SiGe layer. The variations in thickness and composition between two samples grown in the same run were evaluated to be +/- 1.3 and +/- 1.2%, respectively. These results show that uniform layers can be simultaneously obtained on many wafers by the UHV/CVD system.