The as grown films were X-ray amorphous. X-ray reflectivity (XRR) measurements show that the samples have similar densities of 2.25 ± 0.2% g/cm with an interface roughness of less than 0.9 nm whether deposited with or without Xe addition. The density value observed is comparable to the bulk density value of 2.48 g/cm 3 reported for boron-rich boron carbide. Residual film stress obtained by the wafer curvature method shows a tensile stress of ~0.8