HYDROGEN IN POLYCRYSTALLINE SILICON SOLAR-CELL MATERIAL - ITS ROLE AND CHARACTERISTICS

The role and the characteristics of hydrogen in different polycrystall ine silicon material are studied in this paper. The hydrogen diffusion through the grains and the grain boundaries, and its diffusion coeffi cient, are investigated, Moreover, the influence of the oxygen and the carbon contents on the diffusion mechanism of hydrogen in silicon is addressed. Also, it is found that the minority carrier diffusion lengt h of polycrystalline silicon wafers considerably improves when anneale d in hydrogen at high temperatures (>1000 degrees C). Consequently, a significant amount of oxygen is out-diffused from the bulk of the wafe rs, (C) 1998 Published Elsevier Science B.V. All rights reserved.