SPOT IV CHARACTERIZATION - AN EFFECTIVE TOOL FOR RD AND QUALITY CONTROL IN MANUFACTURING OF THIN FILM Si SOLAR MODULES

摘要

A portable system was developed for measuring I-V characteristics of small area (0.5-1 cm~2) thin film Si diodes formed by wet chemical etching or laser ablation process at arbitrary coordinates of the large area solar panel. Mapping the lateral distribution of P, I_(sc), V_(oc) and FF provides detailed information and quick feedback for process development. The different light sources integrated in the system reveal new information about the diode as a PV device and allows separated characterisation of the first and second diodes of the double junction cells. The capacitances of the junctions are also probed with quasi static capacitance method. The quasi static C-V characteristics of the junctions and the intrinsic layer thickness can be derived from pairs of I-V curves as measured with slow and fast voltage ramps. Biasing the double junction diodes in combination with illumination of different wavelengths, the measurement of capacitance curves and the calculation of i-layer thicknesses of both pin diodes are feasible. The simple, quick sample preparation and the short, automatic measurement sequences in combination with the automatic evaluation facilitate rapid feedback for PECVD process development and troubleshooting of regular PV production.