Substrate temperature dependence of hillock, grain, and crystal orientation in sputtered Al–alloy films

Abstract

The effects of substrate temperature during deposition on hillock, grain and crystal orientation were investigated for Al, Al–Ti, Al–Si, Al–Si–Ti, and Al–Cu films. The films were deposited by magnetron sputtering in the substrate temperature range from room temperature to 350 °C and followed by vacuum annealing at 400 °C for 5 min. Hillock density was varied as a function of the substrate temperature in a different manner for each investigated material. The substrate temperature during deposition is a very important factor for suppressing the hillock formation. A close relationship between hillock density and grain size was observed. This was modified when the substrate temperature was changed. This is probably related to the change of grain texture morphology determined by the x-ray diffraction measurements.