Influence of gallium supersaturation on the properties of GaN grown by metalorganic chemical vapor deposition
Influence of gallium supersaturation on the properties of GaN grown by metalorganic chemical vapor deposition
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DOI：
10.1063/1.2952027
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发表时间：
2008-07-01
影响因子：
3.2
通讯作者：
Sitar, Z.
中科院分区：
文献类型：
--
作者：
Mita, S.;Collazo, R.;Sitar, Z.
建立了一个描述低压金属有机物化学气相沉积GaN生长特性的热力学过饱和模型。该模型考虑了在生长界面处发生的简化的GaN化学反应，Ga+NH（3）=GaN+3/2 H（2）。过饱和度以两种方式变化：（1）通过V/III比和（2）通过稀释气体的选择。考虑了两种稀释气体：H（2），一种常用的稀释气体，和N（2），一种反应惰性气体。稀释剂的选择在Ga的过饱和度中起作用;由于H（2）是GaN形成中的产物，因此添加氢显著降低了过饱和度。原子力显微镜显示，表面形态与不同的Ga过饱和度和伯顿-卡布雷拉-弗兰克模型被用来将其与所观察到的螺旋尺寸和梯田宽度。除了生长形貌外，Ga过饱和度也影响n型GaN中载流子的补偿水平。二次离子质谱研究表明，碳掺入的趋势遵循的补偿水平和相反的Ga过饱和。对于有意掺杂Si的样品，发现当碳浓度超过硅浓度时，GaN变成半绝缘的。在一般情况下，它已被证明，在看似不同的条件下的两个生长过程将是等效的，如果相应的Ga过饱和度是相同的。这一发现表明，过饱和度是一个更普遍的参数比任何其他单独的生长参数。(c)2008年美国物理研究所。
A thermodynamic supersaturation model for gallium (Ga) was developed to describe GaN growth characteristics in low-pressure metalorganic chemical vapor deposition. The model takes into account the simplified GaN chemical reaction that occurs at the growth interface, Ga+NH(3)=GaN+3/2H(2). The supersaturation was varied in two ways: (1) by the V/III ratio and (2) by the choice of the diluent gas. Two diluent gases were considered: H(2), a commonly used diluent gas, and N(2), a reaction inert gas. The choice of the diluent played a role in the degree of Ga supersaturation; since H(2) is the product in the GaN formation, the addition of hydrogen significantly lowered the supersaturation. Atomic force microscopy revealed that surface morphology was associated with the different Ga supersaturation and the Burton-Cabrera-Frank model was used to relate it to the observed spiral size and terrace width. In addition to growth morphology, the degree of Ga supersaturation also influenced the carrier compensation level in n-type GaN. Secondary ion mass spectrometry studies identified that the trend of carbon incorporation followed that of the compensation level and inversely that of the Ga supersaturation. For samples intentionally doped with Si, it was found that GaN became semi-insulating when the carbon concentration exceeded that of silicon. In general, it has been shown that two growth processes at seemingly different conditions will be equivalent if the corresponding Ga supersaturation is the same. This finding showed that the supersaturation is a much more universal parameter than any other growth parameter alone. (c) 2008 American Institute of Physics.