Study On The Hardness Of The Sno₂ Type Film With Tribolinderter In-situ Nanomechamical Test System

The SnO₂ type films are an early commercial purpose transparent conducting oxide (TCO) films which are commonly used as the Low-E glass, the electrode of thin film solar cells and the display device. The understanding of physical and chemical properties, especially the intrinsic hardness to this type films is the necessary prerequisite for the application and the protection about the performance. Meanwhile, we can choose the suitable septa and anti-corrosion materials for thin film exactly. According the designing view of material, the goal is to obtain the intrinsic hardness of the film samples. This theme adopted the density functional theory of first principle to calculate the cohesion, bond length and layout of SnO₂ and SnO₂: Sb models. The compound hardness of film samples is tested by in situ nano test system and microhardness testing, and then the intrinsic hardness of film is separated by elastic ball mathematical model and Meyer method. At last, compare with the theoretical value.In the testing process of hardness, we also use the X-Ray fluorecence spectrometer(XRF) to measure the composition of the film,use X-Ray diffraction (XRD) to analysis the crystal structure.By scanning electron microscope (SEM) and field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM),we observe the surface morphology of the film. The surface outline is used to test the thickness.Theoretical research results indicates that there is no difference between the hardness of SnO₂ unit cell and the supercell (2×2×2), while the hardness is larger then the SnO₂ doped with Sb. In the SnO₂ super cell (2×2×2), the hardness value declined with the increased of the number of atoms that Sn were replaced by Sb. The hardness of SnO₂:Sb film made up by industrialization online CVD is tested by in situ nano test system. When SnO₂ film thickness is same and structure is the four rutile structure, the hardness of the film which has larger lattice constant is greater. Considering the film surface roughness will affect the hardness test results of film, the intrinsic hardness is separated from compound hardness by elastic ball mathematical model and then compared with theoretical value. For the SnO₂ type films made up by PVD, the intrinsic hardness is obtained by microhardnesstester combining with Meyer method.