Diffusion-limited kinetics of terrace growth on GaAs(110)
Diffusion-limited kinetics of terrace growth on GaAs(110)
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GaAs(110) 平台生长的扩散限制动力学
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Castonguay
中科院分区：
文献类型：
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作者：
P. Piercy;A. Castonguay
用低能电子衍射(LEED)光斑轮廓分析研究了低能离子轰击GaAs(110)产生的表面粗糙度的热退火动力学，研究了其中的扩散机制。在660-740K温度范围内，在部分退火表面观察到阶梯结构的粗化，平均阶梯宽度L{约x}t{sup{beta}}在两个数量级内呈指数{beta}=0.23-0.26的指数增长，但阶梯高度分布随退火温度变化不大，这为台阶边缘的Ehrlich-Schwoebel势垒提供了证据。LEED分析还发现了一个附加的、低幅度的高度分布，导致界面宽度小于0.03 nm，这被解释为亚表面缺陷周围的弹性变形，并且在退火过程中表现出比平台生长慢得多的松弛动力学。
The kinetics of thermal annealing of surface roughness created by low-energy ion bombardment of GaAs(110) is characterized in situ by a low-energy electron diffraction (LEED) spot profile analysis to investigate the underlying diffusion mechanisms involved. The coarsening of the step-and-terrace structure on the partially annealed surface is observed, showing power-law growth of the average terrace width l{approx}t{sup {beta}} with an exponent {beta}=0.23-0.26 over two orders of magnitude in annealing time t in the temperature range 660-740 K. However, the terrace height distribution is shown to vary little with annealing, providing evidence for an Ehrlich-Schwoebel barrier at step edges. The LEED analysis also detects an additional, low amplitude height distribution contributing an interface width of less than 0.03 nm, which is interpreted as elastic deformation around subsurface defects and exhibits much slower relaxation kinetics during annealing than the terrace growth.