STUDY ON ANNEALING EFFECTS OF AU THIN-FILMS ON SI

We report on the annealing effects of gold thin films deposited on sil icon by analyzing the FTIR, AFM and d.c. conductivity, before and afte r annealing, FTIR spectra show higher IR transmission for samples afte r short time annealing, but the transmission decreases after longer an nealing. The AFM photographs reveal that gold clusters are formed afte r short annealing and consumed by reaction with Si after longer anneal ing, The d.c. I-V measurement shows a nonlinear conductivity of gold t hin films. The thin film resistance becomes lower after longer anneali ng. The I-V behavior can be explained by percolation of silicide clust ers with fractal-like structures. We suggest a mechanism of silicide f ormation for that silicide is formed out of Au cluster and then diffus ed along the Si surface, which leads to less IR transmission but highe r conductivity. The results of FTIR, AFM and I-V measurements are cons istent with our model. (C) 1998 Elsevier Science S.A. All rights reser ved.