Transactions on Electrical and Electronic Materials

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Time Evolution of a High-temperature GaN Epilayer Grown on a Low-temperature GaN Buffer Layer using a Low-pressure MOCVD

  • Chang, Kyung-Hwa (Department of Chemical Engineering, University fo Seoul) ;
  • Cho, Sung-Il (Department of Chemical Engineering, University fo Seoul) ;
  • Kwon, Myoung-Seok (Department of Materials Science and Engineering, University of Seoul)
  • Published : 2006.02.01
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Abstract

In this paper, the time evolution of undoped GaN epilayers on a low-temperature GaN buffer layer grown on c-plane sapphire at a low pressure of 300 Torr was studied via a two-step growth condition in a horizontal MOCVD reactor. As a function of the growth time at a high-temperature, the surface morphology, structural quality, and optical and electrical properties were investigated using atomic force microscopy, high-resolution x-ray diffraction, photoluminescence, and Hall effect measurement, respectively. The root-mean-square roughness showed a drastic decrease after a certain period of surface roughening probably due to the initial island growth. The surface morphology also showed the island coalescence and the subsequent suppression of three-dimensional island nucleation. The structural quality of the GaN epilayer was improved with increasing growth time considering the symmetrical (002) and asymmetrical (102) rocking curves. The variations of room-temperature photoluminescence, background carrier concentration, and Hall mobility were measured and discussed.

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