| SiC is one of the third-generation semiconductor materials, which were developed later than the first (Si and Ge) and the second generation semiconductor materials (GaAs, InP, GaP, InAs, AlAs etc). The heteroepitaxy of the SiC film is important since high quality SiC wafer is expensive and hardly to be achieved. To this day, the heteroepitaxy of SiC is mostly on Si substrate. However, cavities are prone to formatting at the Si/SiC interface due to the large lattice mismatch and thermal expansion coefficient difference between Si and SiC. These cavities degrade film's electric/optical properties and inhibits applications for devices. Oxide of SiC is SiO2 as that of Si. The optically active defects in SiO2 influence not only the optic devices but also the Si- and SiC-based micro-electronic devices. Photoluminescence (PL) is an approach to investigate these optically active defects.This thesis covers mainly two areas: one is the works for suppression of interfacial cavity; the other is PL investigation of optically active defects in low-dimension SiO2.Preparaton, structure and optic/electric properties of SiC film by PS/Si pyrolysis:SiC films are grown on Si substrates by PS/Si pyrolysis in 1 atm ambient Ar, and the growth conditions are optimized. The film growth process is proposed as well. The planar, compact and oriented SiC film was grown at 1250°C, optimized temperature, in quartz crucible. No cavity was observed in the SiC film. The mechanism of cavity formation and suppression was discussed based on the theory of vacancy aggregating. A broad IR absorption band between TO and LO phonon frequency of SiC were explained by Mie's scattering theory. Based on the film growth process, the IR absorption indicated that some carbon atoms diffused into Si substrate and formed dispersed small SiC particles. The thicknesses of SiC films grown at different temperatures were estimated from the IR absorption of these films. It was suggested that the film growth is in 2D mode below 1250°C, in 3D mode above 1250°C. The volatilization of Si and C atom is obvious above 1270°C. A silica layer formatted on the SiC film at the late stages of SiC growth. The sample is actually SiO2/SiC/Si. Moreover, the SiC film grown at optimized condition shows goodish I-V character. The mechanism of the blue PL from the SiC film was also discussed. The PL was attributed to NITs (near-interfacial traps) at the SiO2/SiC interface. As far as know, it is first time to found the NITs' PL. The NITs are important traps at SiO2/SiC interface, with a still unknown nature. NITs is usually observed at SiO2/SiC and SiO2/Si interface by electric measurement. The trapping of electrons by NITs results in a degradation of the channel mobility, particularly at the SiO2/4H-SiC interface. Our conclusion will help to detect NITs by optical methods, the study of NITs and is important to SiC-based MOS devices. High quality SiC film without interfacial cavity were prepared in vacuum (10-3 Pa) and low-pressure (5×104 Pa) ambient Ar by PS/OCS/Si pyrolysis. The optimized growth temperature is 1050°C and the product is 6H-SiC in vacuum condition, while the optimized growth temperature is 1300°C and the main product is 4H-SiC in low-pressure ambient Ar. The reason of growing different SiC polytypes is discussed. It was suggested that suppression of cavity was due to SiO2 layer, which prevent Si atom diffusion and provide Si atom for SiC formation.Investigation of the growth and the PL of the amorphous silica wires.An intense broad blue PL band was observed from the silica wires. The blue PL band is made up of two relative PL peaks at 2.8eV and 3.0eV. Both the PL peaks are broadened by " inhomogeneous broadening effects" due to the glassy state. So the PL band intensity does not almost change from 2.84 to 3.0eV photon energy. The blue PL had been reported in some literatures and were usually attributed to ODC (II) centers of SiO2. However, this attribution is unreliable for lack of the PL's intrinsic properties. We investigated the mechanism and origin of this PL by its intrinsic properties, such as PL decay, PL excitation etc. The results negated that the blue PL is due to ODC (II), and the PL can not be due to any familiar point defect in SiO2. The PL decay excited with 260 nm light can be fitted well using hyperbola. Hyperbolic PL decay suggests the PL relates to the conduction band or the valence band of silica. The fitted parameter implies that the electrons are excited from traps and have large displacement. Based on the location and shape of emission and excitation spectra, it was concluded that the blue PL of SiO2 wires had the same origin as that of SiC film grown by pyrolysis of PS/Si sol-gel coatings. The blue PL of SiO2 wires is from NITs at the SiO2/Si interface.
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