Analysis of threading dislocations in void shape controlled GaN re-grown on hexagonally patterned mask-less GaN

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• 作者：M. Ali^a ; ^{muhammad.ali@tkk.fi} ; A.E. Romanov^b ; ^c ; S. Suihkonen^a ; O. Svensk^a ; S. Sintonen^a ; M. Sopanen^a ; H. Lipsanen^a ; V.N. Nevedomsky^c ; N.A. Bert^c ; M.A. Odnoblyudov^b ; V.E. Bougrov^b
• 关键词：A1. Defects ; A3. Metalorganic vapor phase epitaxy ; A3. Pendeo-epitaxy ; B1. Nitrides
• 刊名：Journal of Crystal Growth
• 出版年：2012
• 期刊代码：49_00220248
• 类别：ch
• 出版时间：1 April, 2012
• 卷：344
• 期：1
• 页码：59-64
• 文件大小：675 K

摘要

In this article, we analyze the behavior of threading dislocations in GaN layers re-grown on hexagonally patterned mask-less GaN. The growth mode of the material with patterned hexagonal morphology changes with the diameter and the periodicity of the hexagonal patterns. The growth mode directly affects the shape of the voids that are formed in this kind of lateral epitaxy. Transmission electron microscopy has been used to study threading dislocations in GaN layers with voids having different sizes and sidewall angles. The results show that a significant number of threading dislocations near the tapered void's surface undergo a 90掳 reorientation in their propagation trajectory whereas almost no dislocations bend in the case of smaller voids having more vertical sidewalls. Different types of dislocations in the vicinity of the voids have also been identified using the invisibility g路b criteria. The full width at half maximum values for XRD 蠅-scan recorded in (002) reflection drop from 256鈥?to 181鈥?as the void sidewall inclination changes from 85掳 to 60掳. A similar dropping trend in the full width at half maximum values for asymmetric diffraction reflections has also been observed.