GaAs原子層エピタキシーのその場観察 : グラヴィメトリック法および表面光吸収法(<特集>「核形成と成長カイネティクス」)

抄録

Two in situ monitoring methods are described for the growth of GaAs by halogen transport atomic layer epitaxy (ALE). First, a gravimetric method is proposed and applied to the GaAs growth. An ALE growth system with a microbalance is developed as a monitoring system. In the conventional method of measurement the growth rate of ALE is obtained as an average value, but the system can directly monitor the growth rate and the surface coverage in each cycle in actual ALE growth conditions. It is shown that the growth of the monomolecular layer unit occurs in each cycle in halogen transport GaAs ALE, and the gravimetric method makes in situ and real-time monitoring of growth rate possible on a submonolayer scale. Next, the epitaxial growth reaction that proceeds on the substrate surface during halogen transport ALE is observed directly with a surface photo-adsorption method (SPA). Based on the in situ gravimetric and optical monitorings, the reaction mechanism is discussed.