Feasible control of laser doping profiles in silicon solar cell processing using multiple excitation wavelengths

Laser doping technique in silicon solar cell processing is now gathering many attentions because of its advantages to be performed at room temperature and in the atmosphere. In order to extend the laser doping utility for the further applications, we tried to control laser doping conditions feasibly by using multi-type of lasers with different wavelength of 532 nm and 355 nm. As the result, doping depth was precisely controlled by changing the wavelength of laser and output power, remaining the highest doping concentration as the same value. Especially, using short wavelength laser, the doping depth could be controlled in the shallower region under 0.2 μm. Moreover, Laser doping technique was applied to form the emitter or back surface field of silicon solar cell as the room temperature process. Even by the shallower doping by short wave length, the effective formation of emitter and back surface field was confirmed.