Evaluation of the ohmic properties of the silver metal contacts of an improved sintering process on the multicrystalline silicon solar cells

In the present study, we have investigated the electrical and ohmic properties of the screen-printed silver metal contacts formed on the heavily doped n emitter region of the multicrystalline silicon solar cells. It shows that the rapid firing of the silver thick-fllm conductor paste at higher temperature results a preferential etching of the silicon surface by the molten glass-frit, on cooling silver sinters concurrently and forms a nearly perfect metal and the semiconductor contact structure. The ohmic properties of the sintered silver metal contacts were characterized by modified three- point probe method, power loss calculation respectively. The best value of specific contact resistance obtained is 10^-4 Omega-cm² for the Ag metal electrode and p-type mc-Si contact structure. The doping level dependence of the pc with the surface doping concentration (N_s) shows a linear relationship between the pc with the inverse of the square root of the surface doping concentration (N_s ^-1/2) as suggested by the theory for the heavily doped semiconductor region.