Ruthenium films were grown by plasma enhanced atomic layer deposition (ALD) on Si(100) and ALD TiN. X-ray diffraction (XRD) showed that the as-deposited films on Si(100) were polycrystalline, on TiN they were (002) oriented. After annealing at 800 C for 60 s, all Ru films were strongly (002) textured and very smooth. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) demonstrated that the lateral grain size of the annealed films was several 100 nm, which was large compared to the 10 nm thickness of the films. No ruthenium silicide was formed by annealing the ALD Ru films on Si(100). Comparison with sputter deposited films learned that this occurred because the ammonia plasma created a SiOxNy reaction barrier layer prior to film growth.