Micro Defects in Nearly Dislocation Free GaN Doped with Mg during High Pressure Crystallization
✍ Scribed by I. Grzegory; J.A. Kozubowski; J. Borysiuk; J.L. Weyher; M. Boćkowski; B. Łucznik; S. Porowski
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 196 KB
- Volume
- 216
- Category
- Article
- ISSN
- 0370-1972
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✦ Synopsis
GaN crystals grown from solutions of liquid gallium alloyed with Mg, at high pressure of nitrogen, are highly resistive and of very good structural quality, evidenced by X-ray diffraction measurements. The high structural quality of these crystals is also confirmed by selective etching of the N-polar (000± ±1) surface in molten KOH±NaOH eutectic which results in EPD as low as few tens on cm 2 . On the other hand, the etching of the Mg-doped crystals in the hot mixture of H 3 PO 4 and H 2 SO 4 beside the etch pits corresponding to dislocations, results in etch hillocks which are not observed for crystals grown without Mg. The hillocks are often arranged into periodic arrays corresponding to growth macrosteps on the crystal surface. In order to identify defects responsible for such etching results the crystals were studied by TEM. The measurements confirmed that the crystals are free of grown-in dislocations, however, bands of microdefects have been observed. Their correlation with the etching results will be shown and discussed in the paper.