Boron Diffusion of the Silicon Solar Cell with BBr3

Abstract

Boron diffusion for the passivation of silicon solar cell is a crucial element of high efficiency solar cells. Comparing with the traditional screen-printed aluminum back surface field (Al-BSF), boron diffusion back surface field has its advantage on improving the surface passivation of silicon solar cell and increasing the effective minority carrier lifetime. For traditional P-type solar cells, the silicon material is becoming less and less. However, the N-type silicon material as a substitute is noticeable. For N-type silicon material, the pn junction is directly formed by boron diffusion. In this paper, comparing with spin-on diffusion method, we mainly focus on the boron diffusion with BBr3. Diffusion temperature, N2 volume and diffusion time etc. elements have the remarkable influence on the number and equality of the sheet resistance, junction depth etc. of the silicon solar cell after boron-diffusion. Masked boron diffusion, one-side erode after boron diffusion also improve the solar cell manufacture technique a lot.