A PROCESS SEQUENCE FOR MANUFACTURE OF ULTRA-THIN, LIGHT-TRAPPING SILICON SOLAR-CELLS

Extremely thin silicon solar cells are of interest for space applications. Performance models show that a surface-passivated, light-trapping silicon solar cell can have optimum thicknesses as thin as 5 μm, and maintain high efficiency down to thicknesses of under 2 μm. Such cells have specific power and extremely good radiation damage tolerance, as well as high efficiency. New methods of fabricating and handling such thin-light-trapping cells using epitaxial growth on a removable substrate are discussed. The substrate provides mechanical support to reduce breakage. When the substrate is removed, a transparent glass superstrate provides the mechanical support. By using a process technology in which a sacrificial lattice-matched CaF2 is used, it is possible to re-use the single-crystal substrate. © 1990.