1/f noise and electromigration in aluminum films: The role of film microstructure and texture

Abstract

The role of crystallographic texture on excess noise and the ability of excess noise to predict the electromigration behavior of pure aluminum films is examined. We report the excess noise and electromigration behavior of pure Al films which were deposited under a variety of conditions to obtain significantly different crystallographic textures. The noise magnitude and the logarithmic slope (α) were measured on three distinct sets of aluminum films as a function of linewidth (∼0.5-2 μm). Previously the electromigration lifetimes of these films were directly related to the (111) volume fraction. This study shows that excess noise is inversely proportional to the (111) volume fraction, suggesting that excess noise may not be measuring the same rate limiting atomic process as electromigration. The effect of film texture combined with a lower noise magnitude with decreasing linewidth implies that grain boundaries are a major source of noise in Al films.