Characterization of graded InGaN/GaN epilayers grown on sapphire-猫眼课题宝

蓝宝石上生长的渐变 InGaN/GaN 外延层的表征

DOI：

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发表时间：

2004

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文献类型：

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作者：

T. Song;S. Chua;E. Fitzgerald;Peng Chen;S. Tripathy

原子力显微镜、扫描电子显微镜、微拉曼和光致发光技术已经被用来表征生长在蓝宝石上的梯度InGaN/GaN薄膜。这些梯度的InGaN/GaN可以用作缓冲，可以缓解蓝宝石上生长的氮化物脱膜中由于晶格和热失配而产生的应变。与传统的两步高温体GaN相比，在具有中间薄GaN层的逐渐渐变的InGaN缓冲层上生长的GaN具有增强的应变弛豫。中间层的作用是在一定厚度后逐渐放松在InGaN层中形成的应变。中间层的最佳生长条件对抑制和填充GaN帽层中的v坑起主要作用，经验发现，在750℃下生长，在1000℃下退火的GaN为10 nm薄层。基于v坑开口尺寸的统计分布，对v坑的形成进行了研究。原子力显微镜、扫描电子显微镜、微拉曼和光致发光技术已经被用来表征生长在蓝宝石上的梯度InGaN/GaN薄膜。这些梯度的InGaN/GaN可以用作缓冲，可以缓解蓝宝石上生长的氮化物脱膜中由于晶格和热失配而产生的应变。与传统的两步高温体GaN相比，在具有中间薄GaN层的逐渐渐变的InGaN缓冲层上生长的GaN具有增强的应变弛豫。中间层的作用是在一定厚度后逐渐放松在InGaN层中形成的应变。中间层的最佳生长条件对抑制和填充GaN帽层中的v坑起主要作用，经验发现，在750℃下生长，在1000℃下退火的GaN为10 nm薄层。从v坑开口大小的统计分布来看，v坑的形成也有一定的规律。

Atomic force microscopy, scanning electron microscopy, micro-Raman, and photoluminescence techniques have been used to characterize graded InGaN/GaN epilayers grown on sapphire. These graded InGaN/GaN can be employed as buffers that can relax the strain arising from the lattice and thermal mismatch in nitride epilayers grown on sapphire. Compared to the conventional two-step high temperature bulk GaN, an enhanced strain relaxation was observed in the GaN grown on a gradually graded InGaN buffer with an intermediate thin GaN layer. The function of the intermediate layer was to progressively relax the strain that built up in the InGaN layer after a certain thickness. The optimum growth conditions of the intermediate layer play a major role in promoting the suppression and filling of the V-pits in the GaN cap layer, and were empirically found to be a thin 10 nm GaN grown at 750 °C and annealed at 1000 °C. Based on the statistical distribution of the size of the V-pits opening, the formation of V-pits was also investigated.Atomic force microscopy, scanning electron microscopy, micro-Raman, and photoluminescence techniques have been used to characterize graded InGaN/GaN epilayers grown on sapphire. These graded InGaN/GaN can be employed as buffers that can relax the strain arising from the lattice and thermal mismatch in nitride epilayers grown on sapphire. Compared to the conventional two-step high temperature bulk GaN, an enhanced strain relaxation was observed in the GaN grown on a gradually graded InGaN buffer with an intermediate thin GaN layer. The function of the intermediate layer was to progressively relax the strain that built up in the InGaN layer after a certain thickness. The optimum growth conditions of the intermediate layer play a major role in promoting the suppression and filling of the V-pits in the GaN cap layer, and were empirically found to be a thin 10 nm GaN grown at 750 °C and annealed at 1000 °C. Based on the statistical distribution of the size of the V-pits opening, the formation of V-pits was als...