Doping of crystalline silicon solar cell by making use of atmospheric and sub-atmospheric plasma jet

Summary form only given. The doping process in the manufacturing of solar cell is to form a p-n junction by the injection of impurity materials into a silicon wafer. The elements of III or V group are used in the doping process during which the dopant materials are diffused thermally into the doping layer. In the conventional process of doping, the furnace or the laser is used with the control of temperature in the doping equipment. In this study, a plasma jet system is used for the doping process by replacing the vacuum furnace doping and the selective emitter laser doping in the manufacturing a crystalline solar cell. The plasma jet doping equipment has been developed with respect to some advantages such as low cost, doping quality controlling, adjusting the doping concentration and depth, and the high concentration of doping, which are advantages over the conventional equipments. When the plasma jet is irradiated to the layer of dopant material, the dopant material is diffused to be doped into the doping layer of wafer. The dopant might be doped by the thermal and electrical reaction between plasma particles and dopant materials. Thermal and electrical control of plasma jet for doping process is by the variation of current and exposure rate. In addition, the plasma jets, single or multi-channels, are used by moving the device in the horizontal and vertical directions to a specific area of the wafer to be doped. Selective doping area with the doping position and shape is controlled by the focusing of plasma jet and the controlling the fineness of emitting plasma. Multiple plasma jets systems are proposed for a large scale wafer doping. The operation method on generating uniform plasma in multiple plasma jets system is introduced. In this experiment, we have two ways of plasma jet devices for doping. One is the atmospheric plasma jet by blowing the gas into the jet device. Another is the sub-atmospheric discharges of gas in an isolated chamber controlled with gas pressure. The several parameters of experiment on the doping conditions are investigated such as gas pressures in the chamber, gas type, electrode structure for focusing of plasma jet, etc. In addition, optimal operational conditions are tested with the diode characteristics and doping depth profile of silicon wafer.