Photovoltaic semiconductor device and method of making same

Abstract

A photovoltaic semiconductor device which is a horizontal multijunction series-array solar battery with a monocrystalline body and having elongate zones of aluminum doped silicon passed entirely through N-type silicon layers by Thermomigration process to connect together epitaxially grown buried P layers. Masked elongate N diffusion zones which are parallel and substantially contiguous to each elongated P zone penetrates at least through the lowest P layer thereby forming an inactive pn junction. A thin shallow layer of P-type material is diffused across the top N-type layer. Topologically continuous photovoltaic junctions exist in each cell of the photovoltaic semiconductor device between the shallow layer of P-type material, the buried layer or layers of P-type material, the elongate zone of aluminum doped silicon, and the N-type silicon thereby forming active pn junctions. Metallic strips, at the other pn junctions formed by the thermomigrated aluminum which are inactive, electrically connect the cells together. A method is disclosed for manufacturing the photovoltaic semiconductor device.