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Etch Pits and Threading Dislocations in GaN Films Grown by Metal-Organic Chemical Vapor Deposition |
| LU Min1,2,3;CHANG Xin4;LI Zi-Lan1,2,3;YANG Zhi-Jian1,2,3;ZHANG Guo-Yi1,2,3;ZHANG Bei1,2,3 |
| 1National Key Laboratory for Artifial Microstructure and Mesoscopic Physics, Peking University, Beijing 100871
2Research Center for Wide-Band Semiconductor Materials, Peking University, Beijing 100871
3Institute of Condense State Physics and Material Physics, School of Physics, Peking University, Beijing 100871
4Center for Electron Microscopy, Health Science Center, Peking University, Beijing 100083 |
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| Cite this article: |
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LU Min, CHANG Xin, LI Zi-Lan et al 2003 Chin. Phys. Lett. 20 398-400 |
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Abstract High quality epitaxial GaN films on (0001) sapphire substrates were grown by a commercial metal-organic chemical vapor deposition system. The etch-pits and threading dislocations in GaN films is studied by a scaning electron microscope (SEM) and a transmission electron microscope (TEM). The SEM images of GaN films etched in mixed acid solution (H3PO4:H2SO4 = 1:3) and molten KOH exhibit notably different etching pit densities of 5 x 108/cm2 and 4 x 107/cm2, respectively, which probably indicate that more kinds of etching pits were revealed when etched in mixed acid solution (H3PO4:H2SO4 = 1:3). Cross section TEM of GaN films with different g vectors showed the portions of different threading dislocations. Theoretical calculation indicates that the lattice and thermal expansion coefficient mismatch may be the main origins of pure edge threading dislocations.
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| Keywords:
68.55.-a
61.72.Ff
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Published: 01 March 2003
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| PACS: |
68.55.-a
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(Thin film structure and morphology)
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61.72.Ff
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(Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.))
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