Optimum hydrogen passivation by PECVD Si/sub 3/N/sub 4/ deposited crystalline silicon solar cells

Abstract

Hydrogen passivation is now used extensively in commercial silicon solar cell fabrication. Hydrogen generally introduced in silicon solar cells to reduce detrimental effect of defects and increase the minority carrier lifetime. Nonetheless, the ways by which hydrogen introduced during processing and hydrogen's subsequent interactions with defect remain poorly understood. The aim of this paper is to increase the understanding at a microscopic level of hydrogenation process and passivation mechanisms for crystalline silicon solar cells. The transition metals are common impurities in silicon that decrease the minority carrier lifetime and degrade the efficiencies of solar cells, therefore the possibility that transition-metal impurities in silicon might be passivated by hydrogen has been of long interest. In our experimental study of transition metal-H complexes in silicon is clearly establish how the structural and electrical properties of these complexes in silicon and have understanding the interaction of hydrogen with them. A promising method to introduce hydrogen into silicon solar cell in order to passivate bulk defects is the post-deposition annealing of hydrogen-rich, Si/sub 3/N/sub 4/ surface layer. The effect of annealing on solar cell has characterized by spectral response and FTIR measurement. It is difficult to detect directly the hydrogen introduced of its small concentration. IR spectroscopy with impurities that can trap hydrogen in the silicon has been carried out to determine the concentration and depth of hydrogen silicon solar cells.