Open Access Version

The crystallization of thin silicon films directly on glass with a material quality comparable to commercially available multi-crystalline silicon wafers is one of the major goals in thin film technology. In the past the resulting poly-crystalline silicon layers fabricated using the solid phase crystallization (SPC) method suffered from a number of shortcomings such as small grains and a high defect concentration which limited the achievable open circuit voltage to values below 500 mV. We were able to overcome those limitations with liquid phase crystallization (LPC) utilizing a continuous wave diode laser or an electron beam. LPC results in poly-Si on glass with randomly oriented grains up to cm in length and mm in width with a very low amount of intra-grain defects. In this work we show how an improved crystallization process in terms of the scanning velocity of the laser, pre-heating of the specimens and the applied laser intensity leads to a changing morphology of the resulting poly-Si layers. Using a well-defined parameter set, we are able to substantially decrease the amount of high angle boundaries which are known from literature to reduce the overall electronic quality and to trigger a preferential surface orientation of {100}. First a-Si:H/c-Si hetero-junction cells fabricated using this advanced crystallization process showed a benefit in open circuit voltage.