Sputter-deposited low-stress boron carbide films

Abstract

Significant challenges have been faced in the manufacturing of low-stress B4C films. Here, we demonstrate a set of process parameters for direct-current magnetron sputter deposition of smooth, high-purity, amorphous B4C films with near-zero total residual stress and with thicknesses up to 10 μm. Films are characterized by a combination of high-energy ion scattering, x-ray diffraction, electron microscopy, and stress measurements based on substrate curvature. In order to facilitate the process transfer to other sputtering geometries, the favorable deposition conditions are correlated with distributions of landing energies and incident angles of depositing species estimated by Monte Carlo simulations of ballistic collisions and gas phase atomic transport. Based on such simulations, a decrease in compressive stress with increasing Ar working gas pressure is attributed to the corresponding broadening of the angular distribution of depositing species and associated atomic shadowing effects.

Coating process parameter influence on thin films for the ATHENA x-ray optics

“…Even so, we do observe similar densities of the films grown in experiment #5 through #8. In the work by Engwall et al 16 , they describe the density decrease in boron carbide film deposited under a high working gas pressure and a low working gas pressure by atomic shadowing of boron and carbon atoms. This relates to the elastic scattering of the sputtered atoms with the argon atoms in the chamber atmosphere.…”

The Influence of B4C Film Density on Damage Threshold Based on Monte Carlo Method for X-ray Mirror

“…However, the film density will also change due to the unstable preparation process. It was also found that the density of B 4 C films varied in different experiments [ 26 , 27 , 28 , 29 , 30 ]. The influence of the density change under irradiation with high energy X-rays is unclear, especially for the damage threshold.…”