Surface Reaction Kinetics in Metalorganic Vapor Phase Epitaxy of GaAs through Analyses of Growth Rate Profile in Wide-Gap Selective-Area Growth
Surface Reaction Kinetics in Metalorganic Vapor Phase Epitaxy of GaAs through Analyses of Growth Rate Profile in Wide-Gap Selective-Area Growth
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DOI：
10.1143/jjap.42.6284
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发表时间：
2003-10
影响因子：
1.5
通讯作者：
H. Oh;M. Sugiyama;Nakano;A. Shimogaki
中科院分区：
文献类型：
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作者：
H. Oh;M. Sugiyama;Nakano;A. Shimogaki
宽间隙选择性区域生长被提议作为获取 GaAs 金属有机气相外延 (MOVPE) 表面动力学信息的探针。使用 SiO2 掩模在图案化衬底上生长砷化镓。几个总压力的特征生长速率增强曲线成功地与二维模拟拟合，仅考虑气相扩散，但掩模边缘附近的曲线除外，它似乎反映了表面扩散。控制分布的唯一参数是 D/ks，即膜前驱体的气相扩散系数 (D) 与表面反应速率常数 (ks) 的比率。 D 的值可以使用 Chapman-Enskog 动力学理论来估计，通过观察传质限制条件下的反应器规模的生长速率曲线来验证其准确性，从而获得 ks 的值。从 ks 转换而来的前体粘附概率在 823 至 973 K 的温度范围内介于 0.06 至 0.33 之间。这些值小于生长模拟中通常假设的统一值。 ks 值作为生长温度的函数进行测量。其活化能在 873 K 左右变化：较高温度为 8 kJ/mol，较低温度为 121 kJ/mol。这些信息不仅对于选择性区域生长过程的设计很重要，而且对于构建更真实的 MOVPE 反应模型也很重要。
Wide gap selective area growth was proposed as a probe for obtaining information of surface kinetics in the metalorganic vapor phase epitaxy (MOVPE) of GaAs. GaAs was grown over patterned substrates using a SiO2 mask. The characterized growth-rate enhancement profiles for several total pressures were successfully fitted with two-dimensional simulation, taking only gas phase diffusion into account, except for the profiles in the vicinity of the mask edge, which seemed to reflect surface diffusion. The only parameter governing the profile was D/ks, the ratio of the gas-phase diffusion coefficient (D) to the surface reaction rate constant (ks) of a film precursor. The value of D can be estimated using the Chapman–Enskog kinetic theory, the accuracy of which was validated by observing a reactor-scale growth-rate profile under the mass-transfer-limited regime, and thus we obtained the value of ks. The sticking probability of a precursor, which was converted from ks, ranged between 0.06 and 0.33 for the temperature range of 823 to 973 K. The values are smaller than unity which was often assumed in growth simulations. The value of ks was measured as a function of growth temperature. Its activation energy changed at around 873 K: 8 kJ/mol for higher temperature and 121 kJ/mol for lower temperature. This information is important not only in the design of a selective-area growth process but also for constructing a more realistic reaction model of MOVPE.