Characterization of excess electrical noise in Al-thin films

Excess electrical noise measurement was used to study the electromigration damage in thin aluminum thin films. Magnitude and frequency exponent for excess electrical noise spectra of 1/f/sup /spl alpha// were measured as a function of the Al-thin film temperature. In this study very seldom excess noise with frequency exponent, /spl alpha/, exactly equal to 1.0 or 2.0 was encountered. The value of /spl alpha/ constantly changed from 0.6 to 2.8. This scattering of the /spl alpha/-value meant that different percentages of various noises did exist in almost every noise spectrum. Computer analysis was used to find the portion of each type of noise present at various frequencies. This analyses showed that the excess noise magnitude is overwhelmingly larger than the thermal noise component when /spl alpha//spl ges/0.8. The excess noise spectra with /spl alpha/>1.2 should be considered 1/f/sup 2/ excess noise and different models have to be considered for their study.