(463d) Effects Of Microstructure And Elemental Composition On Material Properties Of Lpcvd Sic Films For Micro- And Nanosystems

Due to its superior material properties, including high melting point, high hardness, wear resistance, and chemical resistance, silicon carbide is a desirable material for micro- and nanosystems, especially those designed for operation in harsh environments. Using a large-scale low pressure chemical vapor deposition (LPCVD) reactor, polycrystalline silicon carbide films are deposited from the precursors 1,3-disilabutane (DSB) and dichlorosilane (DCS) as well as the dopant precursor ammonia. Material properties, including residual stress, strain gradient, and electrical resistivity, which are important in design of micro- and nanosystems, are characterized as functions of precursor gas mixture and post-deposition annealing conditions. Correlations are found between the deposition details and the material properties.

In order to determine the mechanisms responsible for the material property control, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and grazing incidence X-ray diffraction (XRD) are employed to characterize the film microstructure. Also, electron probe microanalysis (EPMA), dynamic secondary ion mass spectroscopy (SIMS), and X-ray photoelectron spectroscopy (XPS) are used to characterize the film elemental composition. From this analysis, it is postulated that grain size, the ratio of silicon to carbon atoms in the film, and the bonding state of the nitrogen dopant atoms are responsible for the observed material property control.