Hfcvd Method Of Preparation Of Nano-sic And Its Nature

As a promising third generation semiconductor material, SiC has a large band gap, high breakdown voltage, high thermal conductivity, high electron saturation velocity, low dielectric constant, stable radiation and chemical properties. Its particular properties make it an attractive material for optoelectronic devices and high-frequency, high-power, high-temperature electronic devices. Because of the indirect band gap structure of SiC, it can't have efficient photoluminescence as GaN and GaAs. SiC only has weak blue emission at low temperature. In order to improve the photoluminescent efficiency, in this thesis, nano SiC films are prepared by hot filament chemical vapor deposition (HFCVD) technique. We dealed with the growth and characterization of silicon carbide films, and the major results are listed below: 1. In order to reduce the lattice mismatch and expansion mismatch between SiC and Si substrate, the pre-carbonization process was employed to prepare the nano SiC films. And this process can enhance the nucleation density and decrease the size of particles. The optical properties of the films were studied. 2. The H₂ dilution ratio was changed to study the structural properties of the films. From the results, it was considered that the H₂ dilution ratio is an important parameter for affecting the crystal quality of the SiC films by HFCVD. 3. From the influence of different carbonization times to the SiC films, the relationship between the optical characteristic and the structural properties of the films was studied. Based on the results, the PL origin of the SiC films was clarified.