Patent ID: 8105924

Claim:
A semiconductor structure comprising: a semiconductor substrate comprising a vertical stack, from bottom to top, of a semiconductor material layer, a far subcollector doped with dopants of one conductivity type, and an epitaxially grown semiconductor portion; a deep trench located in said semiconductor substrate and extending from a top surface of said epitaxially grown semiconductor portion through said far subcollector and into an upper portion of said semiconductor material layer; a reachthrough region located on and outside a wall of said deep trench, adjoining said far subcollector, including a portion having an epitaxial semiconductor material that is the same as an epitaxial semiconductor material of said epitaxially grown semiconductor portion, and doped with dopants of said one conductivity type, wherein said reachthrough region extends from said top surface of said epitaxially grown semiconductor portion to a depth below a bottom surface of said far subcollector on one sidewall of said deep trench, and is not present on another sidewall of said deep trench that faces said sidewall of said deep trench; a doped fill material located within said deep trench and doped with dopants of said one conductivity type; and a metal contact located on said doped fill material.