The control of conductivity of bulk GaN crystals which are grown by Na flux method.

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 18360149
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Osaka University
• Principal Investigator: MORI Yusuke Osaka University, Graduate School of Engineering, Professor (90252618)
• Co-Investigator(Kenkyū-buntansha): KITAOKA Yasuo Osaka University, Graduate school of engineaing, Division of Electrical Electronic and Information Engineering, Professor (70444560)
• Project Period (FY): 2006 – 2007
• Keywords: GaN / Single crystal / Doping

Research Abstract

The elements of impurities and the origins of impurities were investigated to control conductivity of GaN which were grown by Na flux method. The major impurity incorporated into crystals was turned out to be oxygen. The oxygen concentration in LPE-GaN was ranged from the order of 10^<18> to 10^<19> cm^<-3>. The origin of oxygen was successive corrosion of alumina crucible in the growth period. We searched materials for the crucible which can tolerate Ga-Na mixed metal at high temperature and found the yttrium aluminum garnet (YAG) and yttria to be strong enough for that system. The oxygen concentration in LPE-GaN could be reduced to the order of 10^<16> cm^<-3> using yttria crucible. As for the p-type dopants, it was clarified that Mg element can be doped in the LPE-GaN with the order of 10^<20> cm^<-3>, which is the almost same concentration that adopted in the current devices. Mg doping enabled to increase in the conductivity to the order of 10^6 Ω・cm. On the other hand, Li and Ge could reduce the conductivity to the order of 10^<-2> Ω・cm.
Also, even in the Li, Ge or Mg doped system, large bulk GaN single crystal could be obtained by co-doping of carbon which could significantly suppress the growth of poly-crystals.

Research Products

• [Journal Article] The effect of thermal convection on the liquid phase epitaxy of GaN by the Na flux method. (2007)
  • Author(s): R. Gejo, F. Kawamura, M. Kawahara, M. Yoshimura, Y. Kitaoka, Y. Mori and T. Sasaki
  • Journal Title: Jpn. J. Appl. Phys. 46 Pages: 7689-7692
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] The effect of thermal convection on the liquid phase epitaxy of GaN by the Na flux method. (2007)
  • Author(s): R., Gejo, F., Kawamura, M., Kawahara, M., Yoshimura, Y., Kitaoka, Y., Mori, T., Sasaki
  • Journal Title: Jpn. J. Appl. Phys Vol.46 Pages: 7689-7692
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Growth of large GaN single crystals in carbon added Na flux method (2007)
  • Author(s): M., Tanpo, S., Katsuike, Y., Kitano, M., Imade, N., Miyoshi, F., Kawamura, M., Yoshimura, Y., Kitaoka, Y., Mori, T., Sasaki
  • Organizer: 68th The Japan society of applied physics
  • Place of Presentation: Hokkaido
  • Year and Date: 20070900
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Growth of GaN single crystals in high purity conditions using Na flux method (2007)
  • Author(s): Y., Kitano, S., Katsuike, M., Tanpo, M., Imade, N., Miyosbi, F., Kawamura, M., Yoshimura, Y., Kitaoka, Y., Mori, T., Sasaki
  • Organizer: 68th The Japan society of applied physics
  • Place of Presentation: Hokkaido
  • Year and Date: 20070900
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Growth of the Full-Scale GaN Single Crystal Substrate Using Na Flux Method (2007)
  • Author(s): F., Kawamura, Y., Kitano, M., Tanpo, N., Miyoshi, M., Imade, M., Yoshimura, Y., Kitaoka, T., Sasaki, Y., Mot
  • Organizer: 7th International Conference of Nitride Semiconductors
  • Place of Presentation: Las Vegas
  • Year and Date: 20070800
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] The Effect of Additive of Carbon into the Na Flux on the Growth of GaN Single Crystals (2007)
  • Author(s): M., Tanpo, Y., Kitano, F., Kawamura, M., Yoshimura, Y., Kitaoka, Y., Mori, T., Sasaki
  • Organizer: 7th International Conference of Nitride Semiconductors
  • Place of Presentation: Las Vegas
  • Year and Date: 20070800
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Some attempts for increasing the growth rate in the Na flux method (2007)
  • Author(s): F., Kawamura, Y., Kitano, M., Tanpo, M., Imade, M., Yoshimura, Y., Kitaoka, T., Sasaki, Y., Mori
  • Organizer: 26th Materials Research Symposium
  • Place of Presentation: Shiga
  • Year and Date: 20070600
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Growth of the Full-Scale GaN Single Crystal Substrate Using Na Flux Method (2007)
  • Author(s): F. Kawamura, Y. Kitano, M. Tanpo, N. Miyoshi, M. Imade, M. Yoshimura, Y. Kitaoka, T. Sasaki, Y. Mori
  • Organizer: 7th International Conference of Nitride Semicond uctors
  • Place of Presentation: Las Vegas
  • Year and Date: 2007-09-07
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] The Effect of Additive of Carbon into the Na Flux on the Growth of GaN Single Crystals (2007)
  • Author(s): M. Tanpo, Y. Kitano, F. Kawamura, M. Yoshimura, Y. Kitaoka, Y. Mori, T. Sasaki
  • Organizer: 7th International Conference of Nitride Semicond uctors
  • Place of Presentation: Las Vegas
  • Year and Date: 2007-09-07
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] 炭素添加Na fluxを用いた大型低転位GaN単結晶の育成 (2007)
  • Author(s): M. Tanpo, S. Katsuike, Y. Kitano, M. Imade, N. Miyoshi, F. Kawamura, M. Yoshimura, Y. Kitaoka, Y. Mori, T. Sasaki
  • Organizer: 第68回応用物理学会学術講演会
  • Place of Presentation: 北海道
  • Year and Date: 2007-09-04
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] 高純度環境でのNaフラックス法によるLPE-GaN単結晶育成 (2007)
  • Author(s): Y. Kitano, S. Katsuike, M. Tanpo, M. Imade, N. Miyoshi, F. Kawamura, M. Yoshimura, Y. Kitaoka, Y. Mori, T. Sasaki
  • Organizer: 第68回応用物理学会学術講演会
  • Place of Presentation: 北海道
  • Year and Date: 2007-09-04
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Naフラックス法における成長速度向上に向けた取り組み (2007)
  • Author(s): F. Kawamura, Y. Kitano, M. Tanpo, M. Imade, M. Yoshimura, Y. Kitaoka, T. Sasaki, Y. Mori
  • Organizer: 第26回電子材料シンポジウム
  • Place of Presentation: 滋賀
  • Year and Date: 2007-07-05
  • Description: 「研究成果報告書概要(和文)」より