MICROSCOPIC MECHANISM OF ELECTRICAL NOISE IN CO SI THIN-FILM STRUCTURES/

A microscopic mechanism of the production of electrical fluctuations i n noncrystalline structures has been studied by measuring 1/f noise pa rameters and analyzing microstructure of Co/Si interfaces along the si licide nucleation reaction path. The measured noise power spectral den sity presents the largest fluctuations near the structural (noncrystal line-to-crystalline) transition and the electronic (semiconducting-to- metallic) transition region. The amplitude of the noise spectral densi ty at the frequency of 1 Hz drops more than 3 orders after the nucleat ion of the first cobalt silicide phase. The variation of the noise par ameter is assumed to be an indication of the phase transformation alon g the nucleation reaction path in a Co/Si thin film system. Structural studies suggest that the observed electrical noise might originate fr om cobalt atom movements in reversible processes between different che mical structures.