Two types of growth hillocks (marked by Type I and Type II) have been identified in vapour deposited thin films. Type I develops inside the surface of large crystals, while Type II represents individual single crystals protruded over the average surface area of the film. Formation of Type I hillocks indicates the participation of foreign atoms in the film formation and their accumulation along the moving growth steps developing stable phases. Type II hillocks develop at higher growth rates in preferential crystallographic directions due either to the crystallography of crystals (e.g. Bi), or to the effect of selective uptake of foreign species on the crystallographic faces of different Miller indices developing covering layers on different surface areas controlling also the coalescence of the grains. The correlation between the partial pressure of oxygen and the formation of hillocks in Al films proved the effectivity of the last phenomenon.
ASJC Scopus subject areas
- Nuclear and High Energy Physics