Halogen-Transport Atomic-Layer Epitaxy of Cubic GaN Monitored by In Situ Gravimetric Method

In situ gravimetric monitoring (GM) of atomic-layer epitaxy (ALE) of cubic GaN on a GaN buffer layer/GaAs (001) is investigated using a halogen-transport system with GaCl and NH 3 sources. The cubic GaN growth rate of one monolayer/cycle is obtained at a temperature ranging from 350 to 400°C. It is found that pure cubic GaN can be grown by halogen transport ALE. The growth rate decreases with increasing growth temperature, and a constant growth rate of about 0.45 is observed from 410 to 550°C. In this paper, it is shown that the in situ GM method is a powerful tool for understanding growth mechanism of the group III nitrides, as well as that of GaAs.