Intense photoluminescence (PL) was observed at room temperature from porous SiC samples prepared in electrochemical anodization from nano-crystalline SiC thin films grown on Si (100) substrates by hot filament chemical vapor deposition. Raman scattering spectroscopy and high-resolution transmission electron microscopy confirmed the nano-crystalline structure of the host films. For the porous samples formed under weaker anodization conditions, it was found that prolonged irradiation with ultraviolet (UV) light from a He-Cd laser (325nm, 10mW) can induce an enhanced new PL band and change the peak energy from 1.9eV to 2.1eV at room temperature. A defect model is suggested to explain the UV light induced PL change in porous SiC.

SiCGe/SiC heterojunction structure is required in development of SiC optoelectronic devices and light-activated switching devices. We present in this paper a primary attempt to grow the ternary alloy SiCGe on SiC substrates under varied growth conditions in a conventional hot-wall CVD system. SiH4, GeH4 and C3H8 were employed as silicon, germanium and carbon sources, respectively. The samples were measured by means of SEM, XPS, XRD, optical absorption, etc. Two different growth modes i.e., island growth and porous growth were observed. It has been shown that germanium atoms can be effectively incorporated into the ternary alloys, which makes their optical gaps to be narrowed with increasing Ge content. However, incorporation of Ge induces a heavy lattice mismatch, which limits the film thickness by the formation of mismatch defects. It has been shown that use of a buffer layer can effectively improve the growth quality of the ternary alloy.

In this paper, our work is reported on heteroepitaxial monocrystalline SiC films deposited on single-crystalline (111) silicon by hot filament chemical vapor deposition (HFCVD) with a gas mixture of methane, silane and hydrogen at a low temperature of 780℃. The surface micrography and thickness of SiC films on Si (111) substrate were analyzed by scanning electron microscopy (SEM). The characteristics and crystallinity of the SiC film were examined by X-ray diffrac tometer (XRD), transmission electron microscopy (TEM) and auger electron spectrum (AES). The peaks of Si (111), SiC (111) and SiC (222) planes were observed on the X-ray diffraction spectrum, but not the peaks of the SiC (200) or SiC (220) planes. The diffraction pattern of TEM also indicates that the SiC films are single-crystalline structure. AES shows that the element ratio of silicon and carbon in the SiC film is 1:1.004. The preparation conditions were as follows: a filament temperature of 2100℃, substrate temperature of 780°C, hydrogen flow rate of 100 sccm, methane concentration of 8.0%, silane concentration of 1.0% and a reaction pressure of 150 Pa.

Cubic silicon carbide (3C-SiC) is the most promising material for active devices. Most researches of 3C-SiC epitaxial technology have been focused on chemical vapor deposition (CVD) in the past, but the growth rate of CVD is low. We attempt to grow epitaxial 3C-SiC on Si by sublimation method according to bulk sublimation growth technology. The typical sample is characterized by X-ray diffraction and Raman scattering spectroscopy. The results reveal that the sample is well crystalline.

Growth of SiCGe temary alloy on 6H-SiC in a conventional hot-wall CVD system was initially studied. SiH4, GeH4 and C3H8 were employed as silicon, germanium and carbon source, respectively, while H2 was employed as the carner gas. To reduce the heavy lattice mismatch between the film and the substrate, a 3C-SiC buffer layer was inserted between them in a CVD process. Optimizing the growth conditions was discussed. The samples were measured by means of SEM, SAXRD (Small Angle X-Ray Diffraction). It is shown that use of the 3C-SiC buffer layer is an effective way to improve quality of the ternary alloy.