Forming a vertical PNP transistor

摘要

A transistor (10) is formed by utilizing an isolated well (18) within a thin epitaxial layer (14). A base mask (22) that has a base opening (23) is applied to expose a portion of the isolated well (18). A low resistance collector enhancement (24) is formed within the well (18) by doping a portion of the well (18) through the base opening (23). A base region (26) is formed overlying the collector enhancement (24) by doping the well (18) through the base opening (23). Forming the collector enhancement (24) through the base opening (23), facilitates providing the collector enhancement (24) with a small area thereby minimizing the transistor's (10) parasitic collector capacitance value, collector resistance, and transit time.