Patent ID: 8334451

Claim:
A photovoltaic (PV) cell device comprising: a first semiconductor substrate; a second semiconductor substrate provided directly below the first semiconductor substrate and bonded to the first semiconductor substrate; an insulating layer provided between a bottom surface of the first substrate and the second substrate to electrically isolate the first substrate from the second substrate, the insulating layer being substantially planar; a plurality of PV cells defined on the first substrate, each PV cell including only one n-type region and only one p-type region, the n-type region being formed by performing ion implantation of arsenic on a top surface of the first substrate of said each PV cell to provide a shallow junction depth for the n-type region along a first portion of the top surface of the first substrate, the p-type region being formed in the remaining volume of said each PV cell that is not occupied by the n-type region, the p-type region being formed in said each PV cell along the remaining portion of the top surface of the first substrate and along the entire bottom surface of the first substrate; a plurality of vertical trenches provided in the first substrate to isolate the PV cells, each vertical trench extending from the top surface of the first substrate to the bottom surface of the first substrate, so that each vertical trench terminates at the insulating layer, each vertical trench having substantially perpendicular sidewalls which are doped with an impurity to provide gettering sites; a plurality of isolation structures provided within the vertical trenches, each isolation structure including: a first silicon dioxide isolation layer formed on the doped sidewalls of the trench, and a second isolation layer of undoped polysilicon formed over the first silicon dioxide isolation layer to fill the trench; and an interconnect layer patterned to connect the PV cells to provide X number of PV cells in series and Y number of PV cells in parallel.