Comparative Study of High Temperature Anti-oxidation Property of Sputtering Deposited Stoichiometric and Si-rich SiC Films

Stoichiometric and silicon-rich (Si-rich) SiC films were deposited by Microwave Electron Cyclotron Resonance (MW-ECR) plasma enhanced RF magnetron sputtering method. As-deposited films were oxidized at 800, 900 and 1000 ℃ in air for 60 min. The chemical composition and structure of the films were analyzed by X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and Fourier Transform Infrared spectroscopy (FT-IR). The surface morphology of the films before and after high temperature oxidation was measured by atomic force microscopy. The mechanical property of the films was measured by a Nano-indenter. The anti-oxidation temperature of the Si-rich SiC film is 100 ℃ higher than that of the stoichiometric SiC film. The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction. The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.

Simultaneous laser doping and annealing to form lateral p–n junction diode structure on silicon carbide films

Laser-assisted doping of intrinsic silicon carbide (SiC) films deposited on Si (100) substrates by pulsed laser deposition (PLD) method and its influence on simultaneous annealing of the thin film is studied. PLD grown intrinsic SiC films are transformed to p-type SiC and n-type SiC, using laser-assisted doping in aqueous aluminum chloride and phosphoric solutions, respectively. Simultaneous doping and annealing of the SiC film are observed during laser-assisted doping. By precisely positioning the selectively doped region, lateral p–n diodes are formed on the SiC films without using any mask. Electric characteristics confirmed the formation of a lateral p–n diode structure. Numerical analysis of temperature distribution along the depth of the SiC films explains the mechanism of simultaneous doping and annealing during the laser treatment.

Structure and optical properties of porous SiC film grown by magnetron sputtering on porous anodic aluminium oxide template

Porous fluorescent SiC films were deposited by magnetron sputtering (MS) using porous anodic aluminium oxide (AAO) template. In the first step AAO was carefully placed on the Si substrate and then coated with SiC film using magnetron sputtering at the deposition temperature of 873K for different times. The pore diameter, pore spacing and thickness of the double pass porous AAO template were 300, 450 and 500 nm, respectively. The SiC film deposited for 60min showed macroporous structure with the pore size of 200 to 250 nm and pore spacing of 450 nm. The photoluminescence (PL) spectrum of the porous SiC film ranged from 400 to 700 nm. The band gap of SiC is 2.305 eV, and the phonon energy of phonon participating in PL of SiC is estimated at 0.075 eV. The source of phonon participating in PL of SiC may be from phonon scattering of silica/SiC interface in porous SiC film. The porous AAO template assisted magnetron sputtering is a promising technical processing for the fabrication of macroporous fluorescent SiC film.

Toward on-board microchip synthesis of CdSe vs. PbSe nanocrystalline quantum dots as a spectral decoy for protecting space assets

Fabrication of the reaction chamber using silicon carbide. (A) A schematic sketch of the fabrication flow; (B) a photograph of a transparent 6 inch SiC-on-glass wafer; (C) the surface morphology of the SiC film.

Anomalous Properties of the Dislocation-Free Interface between Si(111) Substrate and 3C-SiC(111) Epitaxial Layer

Thin films of single-crystal silicon carbide of cubic polytype with a thickness of 40–100 nm, which were grown from the silicon substrate material by the method of coordinated substitution of atoms by a chemical reaction of silicon with carbon monoxide CO gas, have been studied by spectral ellipsometry in the photon energy range of 0.5–9.3 eV. It has been found that a thin intermediate layer with the dielectric constant corresponding to a semimetal is formed at the 3C-SiC(111)/Si(111) interface. The properties of this interface corresponding to the minimum energy have been calculated using quantum chemistry methods. It has turned out that silicon atoms from the substrate are attracted to the interface located on the side of the silicon carbide (SiC) film. The symmetry group of the entire system corresponds to P3m1. The calculations have shown that Si atoms in silicon carbide at the interface, which are the most distant from the Si atoms of the substrate and do not form a chemical bond with them (there are only 12% of them), provide a sharp peak in the density of electronic states near the Fermi energy. As a result, the interface acquires semimetal properties that fully correspond to the ellipsometry data.

Effects of the Size of Charged Nanoparticles on the Crystallinity of SiC Films Prepared by Hot Wire Chemical Vapor Deposition

Non-classical crystallization suggests that crystals can grow with nanoparticles as a building block. In this case, the crystallization behavior depends on the size and charge of the nanoparticles. If charged nanoparticles (CNPs) are small enough, they become liquid-like and tend to undergo epitaxial recrystallization. Here, the size effect of SiC CNPs on film crystallinity was studied in the hot-wire chemical vapor deposition process. To do this, SiC nanoparticles were captured under different processing conditions—in this case, wire temperature, precursor concentration and the filament bias. Increasing the temperature of tungsten wires and decreasing the ratio of (SiH4 + CH4)/H2 reduced the size of the SiC nanoparticles. When the nanoparticles were small enough, an epitaxial SiC film approximately 100-nm-thick was grown, whereas larger nanoparticles produced polycrystalline SiC films. These results suggest that the size of the CNPs is an important process variable when growing films by means of non-classical crystallization.