The structure zone model applied to ionized cluster beam films: Al on SiO2

Abstract

In this report, a comparison is made between Al film structure resulting from Al vapor deposition from an effusive source and ionized cluster beam (ICB) deposition from a supersonic nozzle both on flat and V-grooved surfaces. The results are in general accordance with published structure zone models (SZM). However, within the substrate temperature range 80–400°C, the film structures formed by the supersonic nozzle are significantly different from those formed by the effusive source. The acceleration voltage used during ICB deposition also has an important role in determining the film structure. The influence of increasing acceleration voltage is especially marked at 400°C where grain size and morphology differences are easily seen in SEM micrographs. At 400°C, the effusive source produces large grains made up of several grains which have coalesced, as shown by grain boundaries. The supersonic nozzle generates large grains which seem to be single crystals with only a few grains which appear to be bicrystals.On the V-grooved surfaces, at substrate temperature below 400°C, the surface structure of Al at the bottom of the V-groove is the same as that on flat surfaces for both effusive deposition and ICB deposition. But at 400°C, Al grains which are much larger than grains on flat surfaces or on the slope of the V-groove grow along the length of these grooves only by ICB deposition.