The structure of erbium films of 600 nm thickness deposited onto carbon (a-C) and glass substrates at 0.55 and 2.5 nm/s deposition rates for varying substrate temperatures is investigated. The cross section and surface structures are examined by electron microscope. Energy-dispersive x-ray diffraction is utilized for the structure analysis of these films. Results are compared with the results presented in H. Savaloni, M. A. Player, E. Gu, and G. V. Marr (to be published), for erbium films on molybdenum substrates. It is found that to produce films with strong preferred orientation on glass substrates low deposition rate (0.55 nm/s) is favorable. This is opposite to erbium on molybdenum substrates. The grain size of erbium films produced at higher deposition rate is much larger than those at lower deposition rate. The structure of thin films has implications for performance of multilayer reflectors, and preferred orientation may have other applications to x-ray instrumentation.