| LaB6 has an excellent conductivity, thermal stability and chemical stability. It also has cathode surface which can maintain a constant activity, whcich is an ideal material as cathode emitter. It is hard to prepare large-scale LaB6 rode cathode. At the same time, it is economical and practical to prepare large area polycrystalline films. The recent research focus on the emissional and optical properties of LaB6 films deposited on metal, glass or polymer substrates. However, few studies were related with LaB6 films as field emission electron emitter of flat panel displays. Single crystal silicon is an ideal material as substrate for film's investigation. Preparation of LaB6 films with a particular growing direction on silicon substrate is the foundation of producing plane and tip field emission devices. At the same time, the absence of depositing LaB6 films on silicon substrate with different crystal directions highlighted the research significance for basic research.In this paper, LaB6 films have been prepared on single crystal Si (111) substrate by magnetron sputtering method. The influence of sputtering power, argon pressure, substrate bias voltage, substrate temperature and sputtering time on the depositing rate, crystal structure and morphology of the LaB6 films has been investigated. Hence, we got the optimized processing parameter for preparing LaB6 films with good crystalline. The influence of annealing temperature on the deposition rate, molecular structure and crystalline of LaB6 has been studied. The influence of Si (111) and Si (100) substrate on the crystal structure, molecular structure, chemical composition and morphology of LaB6 films has been discussed. The dependence of bonding strength, nano-hardness, elastic modulus and electrical conductivity of the LaB6 films on the processing parameter was investigated systematically. Finally, we researched the high temperature thermal stability of LaB6 films.The results showed that the LaB6 films had smooth surface, compact structure, high crystallization and distinct LaB6 (111) preferred orientation when deposited at the optimized parameters (sputtering power was 44 W, argon gas pressure was 1.0 Pa, substrate bias voltage was-100 V, substrate temperature was 400℃). The LaB6 films began to form crystallization structures when the sputtering time was more than 20 min. But the diffraction peaks were broaden and asymmetric, indicating that the crystalline was poor. As the sputtering time increasing, XRD peaks intensity increased significantly, and the crystallization improved. The LaB6 films presented a regular columnar growth pattern, with the direction perpendicular to the substrates. No chemical reactions or chemicals appeared between LaB6 films and the substrates.The influence of annealing temperature on the crystallization of amorphous LaB6 films was investigated. Part of LaB6 films changed from amorphous to crystal after annealing process at 400℃lasting for 1 h. The films showed smaller particles, smoother surface and higher crystalline with LaB6(100) preferred orientation after annealing process at 500℃. When the annealing temperature increased to 600℃, the diffraction peaks of the LaB6 films broadened and dispersed, revealing poor crystalline. At the same time, the grains grew up abnormally and aggregated.The crystal structure, morphology and molecular structure of LaB6 films deposited on Si (111) and Si (100) substrates were detected. The dominant orientation of films was LaB6 (100) on both substrates. At the same time, the crystalline of films was better and their LaB6 (100) showed more obviously preferred growth when the films were deposited on Si (111) substrate. The atomic ratio of La and B for the films which were deposited on Si (111) and Si (100) substrate was 1:4.12 and 1:2.75 respectively, which both higher than the theoretical ratio of 1:6. The LaB & films deposited on Si (111) substrate had four Raman scattering peaks at 214 cm-1,685 cm-1, 1100 cm-1 and 1242 cm-1, which was consistent with T1u, T2g, Eg and A1g phonon, respectively. The Raman scattering peaks for the LaB6 films which were deposited on Si (100) substrate were lower than those deposited on Si (111) substrate. In addition, the Raman peaks for LaB6 films were broaden than that for the micron powders, which may be related to lattice distortion or internal stress in LaB6 films.High-resolution electron microscopy showed that the LaB6 films had polycrystalline structure with some amorphous component. LaB6 (100) and LaB6 (110) planes existed in the films, but their plane spacing had some differences comparing with that of the conventional materials. This is due to the lattice distortion in the LaB6 films. Both of the LaB6 films had [100] directions as the priority direction on Si (111) and Si (100) substrates.All the LaB6 films had excellent bonding strength with the substrates. The film-substrate bonding strength could reach 17.12 N (sputtering power was 44 W, argon gas pressure was 1.0 Pa, substrate bias voltage was -100 V, substrate temperature was 400℃and sputtering time was 90 min). The load-displacement curves of the films were smooth without break, indicating that the LaB6 films had excellent elastic plastic properties. The changes in hardness of LaB6 films were consistent with their crystalline. And the elastic modulus of the films decreased as the grain size increased.The LaB6 films had low resistivity under different sputtering process, and reached a minimum value of 2.38Ω/□. The electrical conductivity of the films was slightly lower than that of the bulk materials, which was between conductors and insulators. The weight-loss curve for the LaB6 films appeared apparently gain at 793.1℃, which indicated that the LaB6 films were oxidized. The high temperature oxidation resistance of the LaB6 films was inferior to the micron powders.
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