Surface morphology of homoepitaxial GaN grown on non‐ and semipolar GaN substrates
Surface morphology of homoepitaxial GaN grown on non‐ and semipolar GaN substrates
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DOI：
10.1002/pssb.201046346
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发表时间：
2011-03
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影响因子：
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通讯作者：
T. Wernicke;S. Ploch;V. Hoffmann;A. Knauer;M. Weyers;M. Kneissl
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文献类型：
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作者：
T. Wernicke;S. Ploch;V. Hoffmann;A. Knauer;M. Weyers;M. Kneissl
gan层上的M-平面，$（11 {\ bar {2}} 2）$，$（10 {\ bar {\ bar {1}} 2）$和$（10 {\ bar {1}} 1）$ gan substrates由金属有机含量的coptive coptive coptive coptive coptive coptime coptive of fore fore。 Phology展示高度为1-2 µm，横向延伸为50–200 µm，而光滑的丘陵丘陵丘。研究了生长参数对表面形态的影响。原子扩散长度导致丘陵密度，丘陵尺寸和丘陵之间的平滑表面，即使在890°C下，Adatom的迁移率也不会降低。
GaN layers on bulk m‐plane, $(11{\bar {2}}2)$, $(10{\bar {1}}2)$ and $(10{\bar {1}}1)$ GaN substrates were grown by metal organic vapor phase epitaxy. XRD rocking curves have a FWHM of less than 150″, indicating excellent crystalline quality. However in many cases surface morphology exhibits hillocks with a height of 1–2 µm and a lateral extension of 50–200 µm whereas a smooth surface would be desirable for optoelectronic devices. The influence of growth parameters on the surface morphology was studied. The goal was, to constrain the material redistribution, that is necessary to form large hillocks. This was achieved by lowering the adatom diffusion length by a reduction of temperature and an increased reactor pressure. In the case of the $(10{\bar {1}}1)$ and $(10{\bar {1}}2)$ semipolar planes a reduction of the adatom diffusion length leads to a reduction of hillock density, hillock size and a smoother surface between hillocks. However, the m‐plane surface does not react to a reduction of adatom mobility. Even at 890°C and 400 mbar rectangular pyramids cover the surface. In contrast to the other planes, the $(11{\bar {2}}2)$ becomes instable, when the adatom diffusion length is reduced.