Well-defined columnar grains in iron films prepared on seed layers

Abstract

The structure of iron films deposited at an incidence angle of 65° on iron seed layers, which were deposited previously on glass substrates and once exposed to air, was investigated. The substrate temperature was 723 K and the pressure during deposition was 5 × 10 −3Pa. The deposition rate R ranged from 0.13 to 67 nm s −1. Results obtained are as follows (i) Well-defined thick columnar grains (crytallites in zone II in the Movchan-Demchishin model) are observed for R < 3.0 nm s −1 and R>6.0 nm s −1, while equiaxed large grains (zone III) for 3.0 nm s −1⩽ R⩽6.0 nm s −1. (ii) The [100] texture is evolved for R>6.0 nm s −1 in response to the development of well-defined columnar grains. On comparing these results with those for films deposited on the bare glass substrates, it is concluded that the coalescence of crystallites developing from the seed layers is suppressed by the impurities accumulated at the side faces of crystallites.