The research progress in the growth mechanism of Ⅲ-V compound semiconductor by atomic layer epitaxy (ALE) is reviewed, with emphasis on the surface reactions of GaAs. There are two surface reaction mechanisms in the ALE growth of GaAs: one is the adsorbate inhibition mechanism, the other is the selective adsorption mechanism. In the adsorbate inhibition mechanism, the pyrolysis of Ga(CH3)3 occurs on the surface which results in the adsorption of Ga(CH3)χ (χ= 1 or 2). The surface reactions stop automatically because of the steric hindrance effect caused by CH3 ligand in Ga(CH3)χ. In the selective adsorption mechanism, the surface pyrolysis of Ga(CH3 )3 will result in the adsorption of atomic Ga. When the surface is saturated with a monolayer of Ga, the surface reactions stop automatically. The gas phase reactions and the effect of atomic hydrogen in GaAs ALE are also briefly discussed.%介绍了用于外延生长Ⅲ-V族化合物薄膜的原子层外延(ALE)的国内外进展.以GaAs为例,讨论了ALE生长Ⅲ-V族化合物的表面反应机理.GaAs的ALE表面反应机理主要有两种:一种是吸附质阻挡机理,即Ga-(CH3)3在表面发生热解,最终Ga(CH3)x(x=1或2)在表面吸附,依靠Ga(CH3)x中CH3的空间位阻效应,表面反应自动停止;另一种是选择性吸附机理,即Ga(CH3)3在表面热解后形成的吸附物质是Ga原子,当表面完全覆盖一层Ga原子,即表面Ga原子饱和,表面反应自动停止.还介绍了ALE生长中的气相反应以及H原子对ALE生长过程的影响.
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