A far subcollector, or a buried doped semiconductor layer located at a depth that exceeds the range of conventional ion implantation, is formed by ion implantation of dopants into a region of an initial semiconductor substrate followed by an epitaxial growth of semiconductor material. A reachthrough region to the far subcollector is formed by outdiffusing a dopant from a doped material layer deposited in the at least one deep trench that adjoins the far subcollector. The reachthrough region may be formed surrounding the at least one deep trench or only on one side of the at least one deep trench. If the inside of the at least one trench is electrically connected to the reachthrough region, a metal contact may be formed on the doped fill material within the at least one trench. If not, a metal contact is formed on a secondary reachthrough region that contacts the reachthrough region.