CHARACTERIZATION OF PIT MORPHOLOGY OF SPUTTERED AL-1WT-PERCENT-SI-0.5WT-PERCENT-CU ALLOY THIN-FILM

The morphological characteristic of a pit produced by the localized co rrosion of sputtered Al-1wt.%Si-0.5wt.%Cu alloy thin film on silicon w afer in acidic chloride solution was investigated by using scanning el ectron microscopy (SEM) and Auger electron spectroscopy (AES). The pit ting potential was determined from the potentiodynamic polarization me asurement. From the SEM observation, a pit obtained from the potentios tatic experiment in the acidic chloride solution showed a characterist ic feature of circular bands around the pit bottom. The analysis by AE S revealed the circular bands and the center of the pit were mainly co mposed of aluminium oxide and silicon oxide arising from the silicon w afer substrate, respectively. It was suggested that the pit in Al-1wt. %Si-0.5wt.%Cu alloy thin film quickly becomes two dimensional. The mec hanisms of pit initiation and growth for the Al alloy thin film were d iscussed in terms of the two dimensional (2-D) nature of the pit.