Surface morphologies of sputter-deposited aluminum films studied using a high-resolution phase-measuring laser interferometric microscope

Sputter-deposited aluminum (Al) film surface morphologies were studied with a new nondestructive method that incorporates a high-resolution phase-measuring laser interferometric microscope. Good correlation is obtained between rms roughness and reflectivity for various conditions of temperature and argon gas pressure. It should be noted that the rms roughness is much more sensitive than reflectivity when reflectivity exceeds 90%. A drastic change is observed in the temperature dependence of the rms roughness and the skewness at 200 °C. As a result there are changes in Al grain sizes and surface morphologies based on concomitant scanning electron microscope observations. We found that the rms roughness value depends on the resolution of the objective especially when the Al grain sizes are comparable to the resolution.