Driving-in effect and gettering degradation induced by laser doping using borosilicate glass as dopant source

Abstract

In the present work, driving-in effect with a low surface doping concentration and a deep junction after laser irradiation is illustrated by using borosilicate glass formed in the boron spin-on dopant diffusion process as dopant source. PC1D simulation results based on the experimental boron doping profiles demonstrate that the doping modification realized by laser irradiation can achieving an efficiency improvement of 0.13% at most. Meanwhile, no amorphous silicon and rare holes are observed after laser irradiation, indicating a relative low laser damage. Root mean square roughness is introduced to characterize the laser damage, whose variation trend with the laser frequency is opposite to that of effective minority carrier lifetime. Besides, unique gettering degradation effect by taking iron concentration as standard is observed, which is attributed to the re-dissolution and re-segregation process during laser irradiation. The present work will be helpful to deepen the understanding of laser boron doping as well as reduce the laser damage and relative high boron concentration induced by laser doping.