Optimization of Back-Surface Field for Crystalline Silicon Solar Cells and Estimating the Firing Temperature depending on the Amount of Printed Aluminum

Abstract

Optimization of back surface field (BSF) for crystalline silicon solar cells was carried out by Afors-Het simulation software. Thickness and doping concentration parameters were optimized and electrical parameters of solar cells both with BSF and non-BSF were analyzed. The optimum BSF thickness and doping concentration for the crystalline silicon solar cell were determined as 7 µm and 1x1019 cm-3, respectively. A special attention was given to the estimation of peak firing temperature considering the printing amount of aluminum paste in order to form an optimal BSF by the calculations using Al-Si binary phase diagram. It was concluded that the temperature of up to 950oC should be established if an amount of 3 mg/cm2 printed aluminum was used to achieve BSF thickness of 7 µm, where 775 oC would be enough when the amount of aluminum is 8 mg/cm2.Keywords: Afors-Het, back surface field, fire through, silicon solar cell