The thickness of amorphous boron films prepared by ion beam sputter deposition is measured using trasmission electron microscopy (TEM). The point of this method is to hold the preparated films at both side with the deposited metal layers of Pt-Pd by vacuum evaporation or W by ion beam sputtering. Especially, metal layer at outside is effective to except the influence of contamination to be polymerzed in TEM.
Based on the ion beam sputter deposition theory, the density of boron films is calculated. As a result, the film density is found to be independent of thickness. The density of amorphous boron films made by ion beam sputter deposition (ρ=2.4±0.18 g/cm³) is in close agreement with the result obtained by N. N. Greenwood (ρ =2.35 g/cm³).