Boron-doped back-surface fields using an aluminum-alloy process [Si solar cells]

Si solar cell boron-doped back-surface fields (BSFs) have potentially superior performance compared to aluminum-doped BSFs due to the higher solid solubility of boron compared to aluminum. However, conventional boron diffusions require a long, high-temperature step that is both costly and incompatible with many photovoltaic-grade crystalline-silicon materials. The authors examined a process that uses a relatively low-temperature aluminum-alloy process to obtain a boron-doped BSF by doping the aluminum with boron. In agreement with theoretical expectations, they found that thicker aluminum layers and higher boron doping levels improved the performance of aluminum-alloyed BSFs