INVESTIGATION ON THE INFLUENCE OF THE INTENSITY PROFILE ON THE DOPING QUALITY IN LASER CHEMICAL PROCESSING (LCP)

摘要

In this paper detailed investigations about the local doping by laser chemical processing (LCP), a liquid jet coupled laser applied to selective emitter formation, are presented. The focus is on the influence of the laser light intensity profile within the liquid jet cross section on the produced dopant distribution. The inhomogeneous intensity profile produced by the liquid jet being a multimode waveguide was quantitatively measured using a suitable camera setup. Then the measured intensity profile was exported to our existing numerical model, which was developed for the simulation of the basic physical effects of LCP. The simulation results are compared to experimentally produced doping profiles showing very good agreement. This means that the LCP doping process can be well described by our numerical model including the real intensity profile. Furthermore, the observation that an LCP doping effect occurs already at average fluence values below the theoretical threshold for melting of silicon is explained by the local super elevations of the intensity profile.