.sic / Si Thin Film Cvd Preparation Of Research

As one of wide band gap semiconductor materials, Silicon carbide (SiC) is appropriate for the fabrication of electronic devices which operate at extremely high temperature and high radiation, due to its excellent physical and chemical properties. In addition, the one dimension or quasi one-dimension SiC which has great potential application in the field of opto-electronic devices, field emission devices and micro-machine electronics (MEMS) is of significant researching value.SiC films were synthesized by chemical vapor deposition (CVD) technique in this dissertation. SiC thin films were analyized by SEM, EDS, XRD and AFM. The effect of growth parameters on the quality of the SiC thin films was studied. The growth mechanism was discussed.First, SiC thin films were grown by traditional"Two-step Growth Process". The study showed that the carbonization temperature, the carbonization time, the orientation of Si substrate and the total pressure in the reaction chamber are the main factors affecting the quality of carbonization layer. The quality of carbonization layer, the C/Si value and the growth temperature has great influence on the quality SiC film. With good quality carbonization layer, higher substrate temperature,appropriate C/Si value and low reaction gas flow, SiC films with good single-crystalline orientation and smooth surface were grown.In order to overcome the effect of lattice and thermal expansion mismatch between SiC and Si, thermal relaxtion process was introduced into the"Two-step Growth Process". By the thermal relaxation process, undulant Si substrate was formed. SiC thin films were laterally epitaxially grown on the ridges. Comparing with the thin films prepared by traditional"Two-step Growth Process"technique, SiC thin films with smoother surface and better textured degree was obtained by the new process.Finally, SiC films was tried to prepared by VLS technique and it was expected to obtaine better crystalline quality than that grown by vapor growth due to the presentation of liquid phase. The effect of growth parameters on the product was studied. It was found that the growth temperature, the thickness of Ni films, the gas flow rate near the substrate have great influence on resultant. Under proper condition, SiC films with good single-crystalline orientation were obtained. SiC thin films with FWHM value of the rocking curve as low as 0.9°was prepared.