The TiB2 thin films were deposited on steel substrates using RF magnetron sputtering technique with the low normalized substrate temperature (0.1<Ts/Tm<0.2). Microstructure of these films was obtained by field emission scanning electron microscope (FESEM) and the grazing incidence X-ray diffraction (GIXRD) characterization, while the composition of films was obtained using Auger emission spectroscopy (AES) analysis. It was found that the TiB2 thin films were overstoichiometric with the B/Ti ratio at 2.33 and the diffusion of Ti and B atoms on the substrate surface was greatly improved at 350 °C. Moreover, a new dense structure, named “equiaxed” grain structure was observed by FESEM at this substrate temperature. Combined with FESEM and AES analysis, it was suggested that the “equiaxed” grain structure was located in Zone 2 at the normalized substrate temperature as low as 0.18.
TiB2 thin films structure zones 1,2,T equiaxed structure superhard coating auger electron spectroscopy