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Shibuya-ku, Japan

Bu Y.,Osaka University | Imade M.,Osaka University | Kitamoto A.,Osaka University | Yoshimura M.,Osaka University | And 2 more authors.
Journal of Crystal Growth | Year: 2014

We investigated the effect of H2 ratio in carrier gas on oxygen concentration, crystallinity and threading dislocation density (TDD) in GaN layers synthesized from Ga2O vapor and NH3. SIMS analysis revealed that the oxygen concentration in GaN layers decreased with increasing H2 ratios, and achieved 8.72×1017 atoms/cc with a growth rate of 50 μm/h when the H2 ratio was 80%. The full width at half maximum (FWHM) and TDD decreased with increasing H2 ratios. To explain these results, we explored the growth mode at the initial growth stage in H2 ambient, and found that the nucleation rate of the GaN crystal decreased in H2 ambient, resulting in the improvement of crystallinity. © 2014 Elsevier B.V. Source


Imade M.,Osaka University | Bu Y.,Osaka University | Sumi T.,Osaka University | Kitamoto A.,Osaka University | And 4 more authors.
Journal of Crystal Growth | Year: 2012

High-temperature epitaxial growth (>1200°C) of GaN using Ga 2O vapor and NH 3 was performed to increase the crystal growth rate and improve crystal qualities such as surface morphology, crystallinity and oxygen incorporation. Results showed that the growth rate linearly increased with the increasing partial pressure of Ga 2O, P Ga2 O, while the surface morphology and crystallinity degraded, and oxygen concentration in the epilayers increased. When the growth temperature increased, smooth GaN epilayers without the degradation of crystallinity could be grown even at high P Ga2 O, i.e. a high growth rate. In addition, the oxygen concentration decreased as the growth temperature was increased. © 2011 Elsevier B.V. All rights reserved. Source


Bu Y.,Osaka University | Imade M.,Osaka University | Kishimoto H.,Osaka University | Yoshimura M.,Osaka University | And 4 more authors.
Journal of Crystal Growth | Year: 2011

In this study, we investigated the relationship between surface morphology and oxygen concentration in GaN layers synthesized from Ga2O vapor and NH3. The surface morphology of GaN layers changed from rough (with large numbers of pits) to (0 0 0 1) smooth planes with the increase in NH3 concentration. SIMS mapping analysis revealed that the oxygen concentration was on the order of 1017 atoms/cm3, the lowest level obtained in GaN layers synthesized from Ga2O vapor and NH3, at the smooth (0 0 0 1) surfaces. By contrast, high oxygen concentration over 1020 atoms/cm3 was detected at the pitted areas. We concluded that GaN films with low oxygen contamination can be obtained by suppressing pit formation and promoting the smoothness of the (0 0 0 1) surface, even when using Ga2O as the Ga source. © 2011 Elsevier B.V. All rights reserved. Source


Trademark
Itochu Plastics Inc. | Date: 2013-09-03

Chemicals used in industry; [ science and photography, chemicals used in in agriculture, horticulture and forestry except fungicides, herbicides, insecticides and parasiticides; ] * chemicals used in science (other than for medical or veterinary purposes); chemicals used for photographic developers and fixers, chemicals used for growth regulators and fertilizers for plants; * unprocessed artificial resins; unprocessed plastics.


Trademark
Itochu Plastics Inc. | Date: 2016-02-19

Unprocessed plastics.

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