POCl3 diffusion process optimization for the formation of emitters in the crystalline silicon solar cells

A systematic investigation of POCl₃ based diffusion optimization for the formation of homogeneous emitters in P type c-Si solar cells is presented. The gas composition, exhaust rates, flat zone temperature profile have been varied to achieve uniform sheet resistance across each wafer and wafers along the boat. A one standard deviation of ~ 5 ohm/square has been achieved on 125 mm × 125 mm mono like wafers from the initial variation of 37 ohm/square. In addition to the sheet resistance, secondary ion mass spectroscopy, ellipsometry, life time and emitter saturation current density measurements are performed for better understanding of the optimization.