METHOD OF FABRICATING SEMICONDUCTOR DEVICES SUCH AS SOLAR CELLS WITH ANTIREFLECTING COATING

摘要

A process of manufacturing silicon solar cells is described which is characterized by forming on the front surface of a silicon substrate a polysilazane coating by (a) first subjecting the substrate to an ammonia plasma treatment for a predetermined period of time so as to produce hydrogen implantation and (b) subjecting the substrate to a silane and ammonia plasma treatment to obtain additional hydrogen implantation and formation of a polysilazane coating. The polysilazane coating is etched to form a grid electrode pattern, and subsequently the exposed silicon on the front side of the substrate is coated with an adherent coating of a highly conductive metal so as to form a grid electrode. An aluminum coating is applied to the rear side of the substrate so as to form a back electrode. The aluminum coating is heated so as to alloy with the silicon substrate and thereby form an ohmic contact. The ammonia plasma treatment has the effect of enhancing the conversion efficiency of the solar cell by virtue of diffusion of hydrogen into the substrate. The heat treatment for alloying the aluminum tends to cause the implanted hydrogen to diffuse further into the substrate, thereby beneficially altering the bulk diffusion length characteristics of the substrate so as to decrease recombination of the minority carriers produced in response to the incident light.