INTERFACE STATES DISTRIBUTION AND DEEP LEVELS AT POLYCRYSTALLINE SILICON GRAIN-BOUNDARIES - EFFECTS OF THERMAL ANNEALINGS

By means of I-V characteristics deconvolution method, we have determined the potential barrier height E(B)-degrees and the distribution of interface states N(E) in the bandgap at polycrystalline silicon grain boundaries (G.B.'s). We have shown that N(E) is not uniform and thermal annealings, processed in argon atmosphere at more than 500-degrees-C, involve an increase in E-degrees and N(E) and shift the distribution center towards the midgap. This evolution is confirmed by DLTS analysis which have been carried out on the same grain boundaries.