Suppression of lateral autodoping from arsenic buried layer by selective epitaxy capping

An effective way to suppress lateral autodoping from the heavily arsenic-doped buried layer during silicon epitaxy is described. By using this simple technique, collector-substrate capacitance (C/sub cs/) is minimized. This process is ideal for high-speed BiCMOS and bipolar technology. A thin epilayer is first grown selectively on the buried layer. This selectively grown film suppresses the release of arsenic during the subsequent epi growth. High-performance bipolar devices have been fabricated in this epi material. Electrical measurements indicate that the crystalline quality is excellent.<>