In situ monitoring of hydrogen adsorption on (001) Ga surface in GaAs atomic layer epitaxy

In situ monitoring of the growth process in atomic layer epitaxy (ALE) is essential for understanding the growth mechanism. In the present paper, investigation of the chemisorption of hydrogen atoms on the (001) GaAs surface in an atmospheric pressure halogen transport ALE using the surface photo-absorption (SPA) method is reported. Furthermore, the Ga surface is monitored using temperature-programmed desorption (TPD) with SPA. It is shown that Ga atoms on the (001) surface react with and are terminated by hydrogen in the carrier gas and the desorption from the surface occurs by the reverse reaction in the inert carrier gas. The occurrence of these reactions is confirmed by the Langmuir equation of the dissociative isotherm.