The Selective Emitter Doping of P-Type Solar Cells Using Atmospheric Pressure Plasma Jet

Currently, doping process to fabricate solar cells uses both furnace and laser. However, furnace doping has some problems, such as handing problems due to expensive equipment purchase, use of toxic gas, and difficulty in the selective emitter doping of wafer. By contrast, laser doping is easier for selective emitter doping, but it requires expensive laser equipment and causes severe damage to the wafer. In the current work, a study on selective doping was carried out by developing a low-cost atmospheric pressure plasma jet in order to compensate the existing doping problems. The developed atmospheric plasma jet uses Argon (Ar) gas as a process gas. For power, a plasma generating source was manufactured by applying a low frequency (similar to 20 kHz). A shallow-doped (120 ohm/square) p-type wafer was used. The doping profile was analyzed by Secondary Ion Mass Spectroscopy (SIMS) measurement. The depth and, concentration of the doping could be controlled by controlling the plasma current and plasma processing time. With this new doping method, a solar cell with a conversion efficiency of 9.41% was produced.