Patent ID: 9508890
Filing Date: 2016-11-29
CPC Classification: H01L,H01S,Y02E,Y02P

Claim Text:
1. A structure comprising: a mask layer disposed above a top surface of a substrate, the mask layer comprising a non-crystalline material and having an opening defined by non-crystalline sidewalls of the mask layer, the opening exposing an area of the top surface of the substrate, the top surface of the substrate comprising a first crystalline material, the area having a width w and a length l, the non-crystalline sidewalls having a height h, wherein the width w is smaller than the length l, and twice the height h is smaller than the length l; a second crystalline material contacting the first crystalline material in the opening, the second crystalline material being lattice mismatched to the first crystalline material, the second crystalline material having a first region disposed above and proximal to a portion of the top surface of the substrate and having a second region disposed above the first region and above the portion of the top surface of the substrate, no interface comprising a different material being between the first region and the second region in a direction perpendicular to the top surface of the substrate, a majority of defects in the first region of the second crystalline material arising from the lattice mismatch between the first crystalline material and the second crystalline material terminating at the non-crystalline sidewalls; a photovoltaic cell disposed above the second crystalline material, the photovoltaic cell comprising more than one active cell junctions above the second crystalline material and an active cell junction below the top surface of the substrate, the active cell junction below the top surface of the substrate comprising a doped layer in a bottom surface of the substrate, all portions of the doped layer being separated from the mask layer by a portion of the substrate; and an electrical contact disposed on the bottom surface of the substrate.