COBALT DISILICIDE INTERCELL OHMIC CONTACTS FOR MULTIJUNCTION PHOTOVOLTAIC ENERGY CONVERTERS

We have created thin buried films of low resistivity CoSi2 in silicon by ion implantation, and used them to provide intercell ohmic contacts for monolithically stacked multijunction photovoltaic energy converte rs. We have grown epitaxial silicon pn junction diodes by chemical vap or deposition onto the thin film of crystalline silicon formed over th e CoSi2 layer after post-implantation annealing. A single junction pho tovoltaic device with two CoSi2 contacts displayed an open circuit vol tage of 0.60 V and a fill factor of 0.80, while a double junction tand em cell with three CoSi2 interconnects generated 1.2 V, under identica l conditions of illumination with a Nd:YAG laser. These results indica te very low defect levels in the deposited silicon epitaxial layers, a nd excellent functioning of the CoSi2 interconnects.