Atmospheric pressure plasma jets of fine-point doping for the selective emitter of solar cell

Summary form only given. The solar cell manufacturing comprises the diffusion process to form a P-N junction on the silicon wafer. The impurities of III or V group are used in the diffusion process. Those are diffused thermally into the silicon wafer. The low efficiency is caused by the resistance of the silicon wafer between electrodes. The resistance is reduced with the heavy molecular doping in solar-cells while the surface recombination between particles is increased. However, the light atom doping in the solar cell causes the reduction of the surface recombination but increasing the resistance. The SE(selective emitter)-doping is that the impurities lightly diffuse on the surface of silicon wafer except for the heavily doped region under the front electrode. The high doping region brings a low resistance of the wafer between the electrodes. As a result, the solar cell efficiency increases. Most of the equipments for solar cell process are high cost while the plasma jet doping equipments are expected to be a low cost. For the remaining the competition, the process of the solar cell must be a low cost and improves the performance. The plasma jet devices are developed for the doping process by replacing the device of laser doping in the doping of selective-emitter. In this study, the basic characteristics of the plasma jets for doping process are investigated. The thermal characteristics about the plasma current are analyzed. Also the influence of adding wafer and coating dopant on the plasma jet discharge are analyzed with H₃PO₄ used for dopant. When the plasma jet is irradiated to the dopant layer on the wafer, the joule heat is created by plasma current. The dopant is diffused by thermal reaction on the doping layer of the wafer that is investigated by SIMS(secondary ion mass spectrometry). The multi-plasma jets device is prepared for increasing the production efficiency. The light doped wafer is coated by dopant is irradiated by multi-pl- sma jets. The doping depths of the irradiation region were dipper than other side. The doping depths were investigated by SIMS.