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3C-SiC was heteroepitaxially grown on Si(1 1 1) substrates by the low pressure chemical vapor deposition (LPCVD) with a gas mixture of silane, ethane and hydrogen. Under the very low pressure of 30 Pa, we got good single-crystalline SiC films at a low temperature of 900 °C, much lower than the typical deposition temperature above 1200 °C found elsewhere. Their characteristics and crystallinity were examined by X-ray diffraction, infrared absorption, and auger electron spectrum (AES). The SiC peak was found at a 2θ value of 35.8°. The full width at half maximum (FWHM) is only 0.28°, indicating that the SiC film is single crystalline. In the FTIR absorption a peak at 800 cm−1 is observed. In the AES depth profile the film is composed of Si and C with a composition very close to that of stoichiometric SiC. The surface morphology of the film was examined by AFM. These images show the good crystalline of SiC at the surface, and the surface image of a film grown at the initial stage was also observed in order to study the growth mechanism at low temperature and low pressure. [Copyright &y& Elsevier]

Abstract. Epitaxial growth of high-quality hexagonal GaN films on sapphire substrates using light-radiation heating metal-organic chemical vapor deposition (LRH-MOCVD) is first reported. The deposition temperature is 950 Celsius, about 100 Celsius lower than that in normal rf-heating MOCVD growth. The FWHM of GaN (0002) peak of the X-ray diffraction rocking curve is 8.7 arc min. Photoluminescence spectrum of GaN film shows that there is a very strong band-edge emission and no "yellow-band" luminescence. Hall measurement indicates that the n-type background carrier concentration of GaN film is 1.7 x 10[sup 18]cm[sup -3] and the Hall mobility of it is 121.5 cm[sup 2]/V s. It is suggested that the radiation of light in GaN growth enhances the dissociation of ammonia and decreases the disadvantages of the parasite reaction between trimethylgallium and ammonia. [ABSTRACT FROM AUTHOR]

Abstract. Pentagon-shaped silicon wires with linewidth around 300nm are successfully fabricated by using the Si/SiGe epitaxy technique, reactive ion etching, and subsequent selective chemical etching. The nanowires are oxidized in wet O[sub 2] at 750 Celsius and 850 Celsius. The oxide and interface morphology are characterized by cross-sectional scanning electron microscope images. It is found that the oxidized nanowire following oxidation at 750 Celsius still keeps its pentagon shape even if it has been oxidized for 19 h. However, the oxidized samples at 850 Celsius become circular in shape. The oxidation-temperature dependence of the sample shapes is discussed. Our results should be useful in generating silicon nanowires coated with SiO[sub 2] in microelectronic technology with careful selection of the SiO[sub 2] growth temperatures. [ABSTRACT FROM AUTHOR]

Abstract: Selective area epitaxy has been applied to grow GaN stripe templates with side facts, followed by InGaN/GaN multiple quantum well (MQW) structures. Stripes oriented along the direction of [11−20] form smooth triangular {1−101} facets, while stripes in the [1−100] direction produce incomplete coalesced {11−22} side facets with planar (0001) surface under the same growth conditions. Room-temperature luminescence property is investigated by using photoluminescence (PL) and cathodeluminescence (CL) spectra. It is found that uniform emission at 400nm has been obtained for triangular MQWs oriented the direction of [11−20]. With respect to the MQWs grown along the [1−100] direction, large redshift is achieved for the ridge area compared to the sidewall due to the lateral vapor diffusion and surface migration. [Copyright &y& Elsevier]

Abstract: Impact of anisotropic strains on low-frequency dielectric properties and room-temperature polar phases of SrTiO3 epitaxial thin films is investigated. The dielectric properties show a remarkable change as a function of anisotropic strains. The number of room-temperature polar phases is as twice as that of isotropically strained SrTiO3 thin films. [Copyright &y& Elsevier]

Tilting in hydride vapor phase epitaxy grown GaN films fabricated by lateral epitaxial overgrowth (LEO) technique has been investigated using four-circle X-ray diffraction measurements and scanning electron microscopy. Both growth rate and V/III ratio influence this tilt. High growth temperatures result in increased wing tilt. For high V/III ratios, above 10.8, a high growth rate is the main factor leading to increased tilt. For V/III ratios below 10.8, a lower V/III ratio decreases the tilt in LEO GaN because of the presence of excess Ga on the growth front resulting in a change of facet direction. Introduction of additional HCl to the surface of the substrate reduces the wing tilt. The mechanism of the influences of these growth conditions on wing tilt was discussed in detail. [Copyright &y& Elsevier]

The evolution of wing tilt in laterally and epitaxially overgrown (LEO) GaN thick film was studied using cross-sectional transmission electron microscope (TEM) observation and high-resolution X-ray diffraction (XRD). The LEO GaN film was grown by hydride vapor epitaxy (HVPE) on Si(1 1 1) substrate. Horizontally propagating dislocations (HDs) and low density of threading dislocation (TD) in LEO wings were observed in TEM micrographs. Tilt of LEO wing to the GaN seed region was measured as 3.3° at interface of HVPE–GaN/metal organic vapor phase epitaxy (MOVPE)–GaN by selective area electron diffraction, which is much more than that in the surface region estimated as 0.4° by XRD measurements. With φ-scan XRD technique, we found that there exist many differences of tilts and twists of c-axis between the opposite wings on each mask. Asymmetry growth of the opposite wings on SiO2 mask may be due to the flow asymmetry of precursor in vertical reactor. The tilting generation and diminishing increasing with film thickness was discussed too. [Copyright &y& Elsevier]

We introduce a method based on photoelectrochemical (PEC) wet etching that can conveniently investigate the defects and dislocations in laterally overgrown GaN layers by scanning electron microscopy (SEM). The image of SEM illustrates that the dislocation density in homoepitaxial growth region is much higher than in the laterally overgrown region. Also from the SEM image, we can directly identify the region with high density of defects from the perfect region. It is confirmed that the quality of GaN is greatly improved by the epitaxial lateral overgrowth (ELO) technique. The concentration of KOH solution has an effect on etching; when KOH is below 0.02 M, the photo-current increases rapidly according to KOH. After that point, it tents to remain stable at the maximum value of 55 μA. In addition, we find that the photo-current gradually decreases if the etch time is extended. It is probably because more dislocations and defects are revealed. [Copyright &y& Elsevier]