Buried-Contact Subcollector-Well for Vertical PNP Compatible With Trench Isolation
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
This article describes a technique for fabricating a buried-contact to a P+ subcollector of a vertical PNP (VPNP) device formed using selective epitaxy. The buried-contact can be used as a subcollector contact, as an interconnection to the VPNP device and as a substrate contact. The disclosed technique begins by using available sidewall spacer technology to form a buried P+ contact concurrent with formation of the trench lines. The starting material is a P- substrate 1, one normally employed in bipolar subcollector processing. The substrate is ion- implanted with arsenic to form an N-type NPN subcollector 2, then annealed and driven-in. N-epitaxy 3 is then grown and a series of (Image Omitted) dielectrics deposited and patterned to define the trench 4.