M. Orihara

Measurements of the Depth Profile of the Refractive Indices in Oxide Films on SiC by Spectroscopic Ellipsometry

The depth profiles of the refractive indices in thermally oxidized films on SiC have been measured by spectroscopic ellipsometry. Oxide films etched at an angle were used to obtain the depth profiles of the refractive indices in the oxide films. The apparent refractive indices napp and thicknesses have been evaluated, assuming that the films have optically uniform single layer structures. The experimental results show that the values of napp increase with oxide film thickness, and approach the values for oxide films on Si at around 60 nm in thickness. This feature is almost the same as the changes of refractive indices of oxide films with oxidation time reported previously. These results reveal that the oxide films are not optically uniform and that the optical properties change with depth from the surface. It has been found that the film structure model where the oxide film is composed of two layers, a thin interface layer around 1 nm in thickness with a higher refractive index than those of SiC and SiO2 and a stoichiometric SiO2 layer, the thickness of which changes with film thickness, can explain the thickness dependence of napp observed. These results suggest that there exists an interface layer with high refractive indices at oxide film/SiC interfaces.

Microstructures of InN film on 4H-SiC （0001） substrate grown by RF-MBE

InN film was grown on 4H-SiC (0001) substrate by RF plasma-assisted molecular beam epitaxy (RF-MBE). Prior to the growth of InN film, an InN buffer layer with a thickness of ~ 5.5 nm was grown on the substrate. Surface morphology, microstructure and structural quality of InN film were investigated. Micro-structural defects, such as stacking faults and anti-phase domain in InN film were carefully investigated using transmission electron microscopy (TEM). The results show that a high density of line contrasts, parallel to the growth direction (c-axis), was clearly observed in the grown InN film. Dark field TEM images recorded with diffraction vectors g = 11

High Cubic‐Phase Purity InN on MgO (001) Using Cubic‐Phase GaN as a Buffer Layer

\overline{2}

High Resolution X-Ray Diffraction and Raman Scattering Studies of Cubic-Phase InN Films Grown by MBE

0 and g = 0002 revealed that such line contrasts evolved from a coalescence of the adjacent misoriented islands during the initial stage of the InN nucleation on the substrate surface. This InN nucleation also led to a generation of anti-phase domains.

TEM Analysis of Structural Phase Transition in MBE Grown Cubic InN on MgO (001) by MBE: Effect of Hexagonal Phase Inclusion in an C-Gan Nucleation Layer

High cubic‐phase purity InN films were grown on MgO (001) substrates by molecular beam epitaxy with a cubic‐phase GaN buffer layer. The cubic phase purity of the InN grown layers has been analyzed by high resolution X‐ray diffraction, μ‐Raman scattering and transmission electron microscopy. It is evidenced that the hexagonal‐phase content in the InN overlayer much depends on hexagonal‐phase content in the cubic‐phase GaN buffer layer and increases with increasing the hexagonal‐phase GaN content. From Raman scattering measurements, in addition, the InN layer with lowest hexagonal component (6%), only Raman characteristics of cubic TOInN and LOInN modes were observed, indicating a formation of a small amount of stacking faults, which does not affect on vibrational property.

RF-MBE growth of a-plane InN on r-plane sapphire with a GaN underlayer

We demonstrate the use of high resolution X-ray diffraction and Raman scattering to assess the generation of hexagonal-phase in the cubic-phase InN (c-InN) films on MgO substrates grown by molecular beam epitaxy with a cubic-phase GaN buffer layer. The X-ray reciprocal-lattice space mapping was used to examine the hexagonal-phase generated on the cubic (111) planes in the c-InN films. Ratio of hexagonal to cubic components in the c-InN grown layers was estimated from the ratio of the integrated X-ray diffraction intensities of cubic (002) and hexagonal (10-11) reflections measured by ω–scans. Amount of hexagonal-phase presented in the c-InN films was determined in the range of 6 to 24%. It was found that the Raman characteristics are also sensitive to hexagonal-phase presented in the c-InN films. For the lowest amount of hexagonal-phase (6%), only Raman scattering characteristics of c-InN was observed, indicating formation of a small amount of stacking faults, which not affected on the vibrational property. Based on our results, relatively easy access to the generation of hexagonal-phase suggests that it may be very useful for HRXRD and Raman scattering measurements of c-InN.

RF-MBE growth of cubic InN films on MgO (001) substrates

In this paper, we introduced dbcube topology for Network-on Chips(NoC). We predicted the dbcube topology has high power and low latency comparing to other topologies, and in particular mesh topology. By using xmulator simulator,we compared power and latency of this topologyto mesh topology. Finally, it is demonstrated that the network has higher power and lower latency than the mesh topology.