Effect of N to Ga flux ratio on the GaN surface morphologies grown at high temperature by plasma-assisted molecular-beam epitaxy
Effect of N to Ga flux ratio on the GaN surface morphologies grown at high temperature by plasma-assisted molecular-beam epitaxy
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DOI：
10.1063/1.1634388
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发表时间：
2004-01-15
影响因子：
3.2
通讯作者：
Hsieh, KY
中科院分区：
文献类型：
--
作者：
Tsai, JK;Lo, I;Hsieh, KY
研究了等离子体辅助分子束外延生长GaN外延膜的表面形貌。我们发现，当在高温下生长时，表面形态对N与Ga的通量比（N/Ga）敏感（即，788 ℃）。在该温度下，即使在富Ga条件下，我们也没有观察到表面上的大尺寸Ga液滴。此外，我们发现了过渡从二维（2D）到三维（3D）的增长在中间Ga稳定的制度。生长速率的斜率不同：在2D生长模式中观察到斜率=（0.39+/-0.06），在3D生长模式中观察到斜率=（0.14+/-0.03）。在高N/Ga比下，位错总浓度降低，混合穿透位错浓度在N/Ga=22.5时有最小值。通过与霍尔载流子浓度结果的比较，我们发现混合穿线位错对电子载流子的数量有影响。(C)2004年，美国物理学会。
The surface morphology of GaN epitaxial films grown by plasma-assisted molecular-beam epitaxy has been investigated. We found that the surface morphology was sensitive to the N to Ga flux ratio (N/Ga) when grown at a high temperature (i.e., 788degreesC). At that temperature, we did not observe large sized Ga droplets on the surface even at Ga-rich conditions. Furthermore, we found a transition from two-dimensional (2D) to three-dimensional (3D) growth in the intermediate Ga-stable regime. The slope of the growth rate was different: Slope=(0.39+/-0.06) was observed in the 2D-growth mode and (0.14+/-0.03) in the 3D-growth mode. In the high N/Ga ratio, the total dislocation concentration was reduced, and the mixed threading dislocation concentration had a minimum value at N/Ga=22.5. By comparing with the Hall carrier concentration results, we found that the mixed threading dislocations influence the number of electronic carriers. (C) 2004 American Institute of Physics.