Effect of magnetic field on the growth of Be films prepared by thermal evaporation

Grain refinement of beryllium deposits is studied as a significant subject for beryllium capsule in the Inertial Confinement Fusion project. The Be films were prepared on the Si (1 0 0) substrates by thermal evaporation with and without a magnetic field, respectively. The two separate groups of prepared Be films were characterized. The results showed the grain diameter in the Be film transited from 300 nm to 18 nm and the surface roughness of the Be film decreased from 61 nm to 3 nm by application of the magnetic field during the deposition process of Be coating. However, the Be film grown with the magnetic field was easily oxidized in comparison with that grown without magnetic field due to the refined grains, and the oxidation was gradually decreased with the increase of etching depth in the Be film. The reason for grain refinement of Be film was also qualitatively described.