Hot-mesh Chemical Vapor Deposition Research Articles

Effect of Growth Pressure on Structural Properties of SiC Film Grown on Insulator by Utilizing Graphene as a Buffer Layer

Heteroepitaxial growth of silicon carbide (SiC) on graphene/SiO<sub>2</sub>/Si substrates was carried out using a home-made hot-mesh chemical vapor deposition (HM-CVD) apparatus. Monomethylsilane (MMS) was used as single source gas while hydrogen (H<sub>2</sub>) as carrier gas. The substrate temperature, tungsten mesh temperature, H<sub>2</sub> flow rate and distance between mesh and substrate were fixed at 750 °C, 1700 °C, 100 sccm and 30 mm, respectively. The growth pressures were set to 1.2, 1.8 and 2.4 Torr. The growth of 3C-SiC (111) on graphene/SiO<sub>2</sub>/Si were confirmed by the observation of θ-2θ diffraction peak at 35.68°. The diffraction peak of thin film on graphene/SiO<sub>2</sub>/Si substrate at pressure growth is 1.8 Torr is relatively more intense and sharper than thin film grown at pressure growth 1.2 and 2.4 Torr, thus indicates that the quality of grown film at 1.8 Torr is better. The sharp and strong peak at 33° was observed on the all film grown, that peak was attributed Si(200) nanocrystal. The reason why Si (200) nanocrystal layer is formed is not understood. In principle, it can’t be denied that the low quality of the grown thin film is influenced by the capability of our home-made apparatus. However, we believe that the quality can be further increased by the improvement of apparatus design. As a conclusion, the growth pressures around 1.8 Torr seems to be the best pressures for the growth of heteroepitaxial 3C-SiC thin film.

Graphene as a Buffer Layer for Silicon Carbide-on-Insulator Structures

We report an innovative technique for growing the silicon carbide-on-insulator (SiCOI) structure by utilizing polycrystalline single layer graphene (SLG) as a buffer layer. The epitaxial growth was carried out using a hot-mesh chemical vapor deposition (HM-CVD) technique. Cubic SiC (3C-SiC) thin film in (111) domain was realized at relatively low substrate temperature of 750 °C. 3C-SiC energy bandgap of 2.2 eV was confirmed. The Si-O absorption band observed in the grown film can be caused by the out-diffusion of the oxygen atom from SiO2 substrate or oxygen doping during the cleaning process. Further experimental works by optimizing the cleaning process, growth parameters of the present growth method, or by using other growth methods, as well, are expected to realize a high quality SiCOI structure, thereby opening up the way for a breakthrough in the development of advanced ULSIs with multifunctionalities.

Epitaxial Growth of GaN Films by Pulse-Mode Hot-Mesh Chemical Vapor Deposition

Intermittent gas supplies for hot-mesh chemical vapor deposition (CVD) for the epitaxial growth of gallium nitride (GaN) films were investigated to improve film crystallinity and optical properties. The GaN films were deposited on SiC/Si(111) substrates using an alternating-source gas supply or an intermittent supply of source gases such as ammonia (NH3) and trimethylgallium (TMG) in hot-mesh CVD after deposition of an aluminum nitride (AlN) buffer layer. The AlN layer was deposited using NH3 and trimethylaluminum (TMA) on a SiC layer grown by carbonization of a Si substrate using propane (C3H8). GaN films were grown on the AlN layer by a reaction between NHx radicals generated on a ruthenium (Ru)-coated tungsten (W) mesh and TMG molecules. After testing various gas supply modes, GaN films with good crystallinity and surface morphology were obtained using an intermittent supply of TMG and a continuous supply of NH3 gas. An optimal interval for the TMG gas supply was also obtained for the apparatus employed.

The growth of GaN films by alternate source gas supply hot-mesh CVD method

Gallium nitride (GaN) films and Aluminium nitride (AlN) layers were deposited on SiC/Si (111) substrates by an alternating source gas supply or an intermittent supply of a source gas such as ammonia (NH 3), trimethylgallium (TMG) or trimethylaluminum (TMA) in a hot-mesh chemical vapor deposition (CVD) apparatus. The AlN layer was deposited as a buffer layer using NH 3 and TMA on a SiC layer grown by carbonization on Si substrates using propane (C 3H 8). GaN films were grown on an AlN layer by a reaction between NH x radicals generated on a ruthenium (Ru) coated tungsten (W)-mesh and TMG molecules. An alternating source gas supply or an intermittent supply of one of the source gases during the film growth are expected to be effective for the suppression of gas phase reactions and for the enhancement of precursor migration on the substrate surface. By the intermittent supply of alkylmetal gas only during the growth of the AlN layer, the defect generation in the GaN films was reduced. GaN film growth by intermittent supply on an AlN buffer layer, however, did not lead to the improvement of the film quality.

Growth of GaN Films by Hot-Mesh Chemical Vapor Deposition Using Ruthenium-Coated Tungsten Mesh

GaN films were grown on AlN/SiC/Si substrates by hot-mesh chemical vapor deposition (CVD) using ruthenium (Ru)-coated tungsten (W)-mesh. When using the Ru-coated mesh, the crystallinity of the GaN films did not degrade until a mesh temperature of 1000 °C, while the crystallinity markedly degraded at lower than 1100 °C when using the W-mesh. From the photoluminescence (PL) spectra of GaN films grown using the Ru-coated W-mesh, strong near-band-edge emission without yellow luminescence can be observed. In order to elucidate the difference in the decomposition efficiency of ammonia gas, the hydrogen radical density generated by the heated W-mesh and Ru-coated mesh was also evaluated using tungsten phosphate glass plates.

Epitaxial Growth of SiC on Silicon on Insulator Substrates with Ultrathin Top Si Layer by Hot-Mesh Chemical Vapor Deposition

The epitaxial growth of SiC on silicon-on-insulator (SOI) substrates with an ultrathin (<10 nm) top Si layer by hot-mesh chemical vapor deposition (CVD) was investigated. This method utilizes heated tungsten wires arranged in a mesh, which promotes the high decomposition efficiency of H2 gas. Using the hot-mesh CVD method, SiC epitaxial films were successfully grown on SOI substrates without voids being formed, which are formed readily in thin (<100 nm) top Si layers at temperatures above 800 °C. Some micropatterns for micro-electro-mechanical systems were fabricated on SiC on insulator (SiCOI) structure substrates by reactive ion etching and wet etching.

Growth of GaN on SiC/Si substrates using AlN buffer layer by hot-mesh CVD

GaN films were grown on SiC/Si (111) substrates by hot-mesh chemical vapor deposition (CVD) using ammonia (NH 3) and trimetylgallium (TMG) under low V/III source gas ratio (NH 3/TMG = 80). The SiC layer was grown by a carbonization process on the Si substrates using propane (C 3H 8). The AlN layer was deposited as a buffer layer using NH 3 and trimetylaluminum (TMA). GaN films were formed and grown by the reaction between NH x radicals, generated on a tungsten hot mesh, and the TMG molecules. The GaN films with the AlN buffer layer showed better crystallinity and stronger near-band-edge emission compared to those without the AlN layer.

SiCOI structure fabricated by catalytic chemical vapor deposition

Epitaxial growth of SiC on SOI substrates using a hot-mesh chemical vapor deposition (CVD) technique was investigated. This technique utilizes a catalytic reaction involving hot tungsten wires arranged in a mesh structure. Using this hot-mesh CVD method, SiC epitaxial growth on SOI substrates with a thin top Si layer was realized without formation of voids, which form readily in the thin Si top layer at temperatures above 800 °C. The SiC film grown on an SOI structure exhibited a large gage factor (GF) of − 27, which is approximately the same as that (GF = − 31.8) of a SiC epitaxial film on Si(100) grown at 1360 °C using atmospheric pressure CVD.

SiCOI Structure Fabricated by Hot-Mesh Chemical Vapor Deposition

The growth of 3C-SiC on thermal oxide layer of Si (SiO2) was investigated by hot-mesh (HM) chemical vapor deposition (CVD), which utilizes hot tungsten (W) wires of a mesh structure as a catalyzer. The SiC films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and cross sectional transmission electron microscopy (TEM). From the XRD spectra of SiC films grown on SiO2 layer, (100) oriented SiC films were grown at the substrate temperatures of 750-800°C and the mesh temperature of 1600°C, while polycrystalline SiC films were grown at the substrate temperature above 900°C. From the data of FT-IR, TEM and the growth rate, the growth characteristics of SiC crystal by HMCVD were discussed.

Characteristics of SiC Heteroepitaxial Growth on Si by Hot-Mesh Chemical Vapor Deposition

The heteroepitaxial growth of 3C-SiC films on Si(100) substrates by the hot-mesh chemical vapor deposition (HM-CVD) method using monomethylsilane as a source gas was investigated. From the results of X-ray diffraction spectra, 3C-SiC crystal was epitaxially grown on Si substrates at substrate temperatures above 750°C. The SiC/Si interface was observed by cross-sectional scanning electron microscopy, and was confirmed to be void-free and smooth. The density of hydrogen radicals supplied to the substrate surface during the growth was also estimated measuring the optical absorbance change of tungsten phosphate glass plates. From the dependence of the growth rate on substrate temperature, the mechanism of SiC film growth by HM-CVD was considered.

Epitaxial Growth of Hexagonal GaN Films on SiC/Si Substrates by Hot-Mesh CVD Method

Gallium nitride (GaN) films were grown on SiC/Si(111) substrates by hot-mesh chemical vapor deposition (CVD) using trimethylgallium (TMG) and ammonia (NH3). A SiC buffer layer was formed by carbonization on the Si(111) substrates using propane (C3H8). GaN epitaxial films were grown on the SiC layer by the reaction between NHx radicals generated on a tungsten hot-mesh surface and TMG molecules. From the X-ray diffraction pattern, the GaN epitaxial films grown by the two- or three-step growth technique at the substrate temperatures of 600°C and 800°C to 1000°C and the hot-mesh temperature of 1200°C showed good crystallinity. Photoluminescence spectra of GaN films grown by the three step growth technique showed a strong near-band-edge emission and a weak yellow luminescence.

Low-Temperature Heteroepitaxial Growth of SiC on (100) Si Using Hot-Mesh Chemical Vapor Deposition

The crystal growth of 3C-SiC films on (100) Si substrates by the hot-mesh chemical vapor deposition (HMCVD) method using monomethylsilane (MMS) as a source gas was investigated. A mesh structure of hot tungsten (W) wire was used as a catalyzer. At substrate temperatures above 750°C and at a mesh temperature of 1600°C, 3C-SiC crystal was epitaxially grown on Si substrates. From the X-ray rocking curve spectra of the (311) peak, SiC was also epitaxially grown in the substrate plane. From the dependence of growth rate on substrate temperature and W-mesh temperature, the growth mechanism of SiC films by HMCVD was considered.

Hot-mesh Chemical Vapor Deposition for 3C-SiC Growth on Si and SiO2

AbstractThe crystal growth of SiC films on (100) Si and thermally oxidized Si (SiO2/Si) substrates by hot-mesh chemical vapor deposition (HMCVD) using monomethylsilane as a source gas was investigated. A mesh structure of hot tungsten (W) wire was used as a catalyzer. At substrate temperatures above 750°C and at a mesh temperature of 1600°C, 3C-SiC crystal was epitaxially grown on (100) Si substrates. From the X-ray rocking curve spectra of the (311) peak, SiC was also epitaxially grown in the substrate plane. On the basis of the X-ray diffraction (XRD) measurements, on the other hand, the growth of (100)-oriented 3C-SiC films on SiO2/Si substrates was determined to be achieved at substrate temperatures of 750-800°C, while polycrystalline SiC films, at substrate temperatures above 850°C. From the dependence of growth rate on substrate temperature and W-mesh temperature, the growth mechanism of SiC crystal by HMCVD was discussed.

Hot-mesh CVD for growth of GaN films on (100) GaAs

Gallium nitride (GaN) films were grown on (100) GaAs substrates by hot-mesh chemical vapor deposition (CVD). A nitrided layer was also formed by the NH x radicals generated on a tungsten hot mesh surface. Nitridation conditions for the growth of GaN films with a cubic-type structure were investigated. Compared with the GaN films grown by hot-filament CVD, the GaN films grown by hot-mesh CVD on the GaAs surface layer nitrided at a substrate temperature of 550 °C, a mesh temperature of 1200 °C and an ammonia (NH 3) pressure of 130 Pa have a more predominant cubic phase.