Growth regimes during homoepitaxial growth of GaN by ammonia molecular beam epitaxy
Growth regimes during homoepitaxial growth of GaN by ammonia molecular beam epitaxy
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氨分子束外延 GaN 同质外延生长过程中的生长机制
DOI：
10.1063/1.4749262
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发表时间：
2012
影响因子：
3.2
通讯作者：
J. Speck
中科院分区：
文献类型：
--
作者：
A. Corrion;Feng Wu;J. Speck
在不同的NH3:Ga通量比和生长温度下，采用氨分子束外延法在金属-有机化学气相沉积模板上生长c平面GaN薄膜，并利用原子力显微镜、反射高能电子衍射和透射电子显微镜对薄膜进行了表征。根据生长模式和薄膜性质，确定了三种不同的富氮生长模式——不稳定的逐层生长、准稳定的阶梯流动和位错介导的点蚀。此外，在镓滴积累的条件下，观察到阶跃流动生长。结果表明，氨mbe的阶梯流生长存在富镓和富氮两种模式。观察了生长模式的不稳定性和土丘的形成，并在台阶边缘能量势垒对附原子在阶地上扩散的背景下进行了讨论。
c-plane GaN films were grown by ammonia molecular beam epitaxy on metal-organic chemical vapor deposition templates for a wide range of NH3:Ga flux ratios and growth temperatures, and the resulting films were characterized using atomic force microscopy, reflection high-energy electron diffraction, and transmission electron microscopy. Three distinct nitrogen-rich growth regimes—unstable layer-by-layer, quasi-stable step flow, and dislocation-mediated pitting—were identified based on the growth mode and film properties. In addition, step flow growth was observed under conditions of gallium droplet accumulation. The results indicate the existence of two regimes for step-flow growth of GaN by ammonia MBE—both gallium-rich and nitrogen-rich. Growth mode instabilities and mound formation were observed and are discussed in the context of a step-edge energy barrier to adatom diffusion over a terrace.