Optical in-situ analysis of GaAs/AlAs/GaAs and GaAs/(Al)GaAs/GaAs atomic layer growth using GaCl3, AlCl3 and AsH3

Atomic layer growth of AlAs and AlGaAs were tried by alternate supply of GaCl3, AlCl3 and AsH3, and the growth process was monitored by an optical method such as the surface photo-absorption (SPA) method and the optical interference method. Although atomic layer epitaxy (ALE) of GaAs can be performed by alternate supply of GaCl3 and AsH3, that of AlAs on GaAs could not be obtained, probably due to surface oxidation of AlAs, AlAs, however, could be grown by simultaneous supply of AlCl3 and AsH3. It was confirmed by the SPA signal that if the AlCl3-adsorbed AlAs surface is exposed to GaCl3, the adsorbed AlCl3 is replaced by GaCl and/or GaCl3 and GaAs ALE growth on AlAs can be performed. A slightly Al-containing (Al)GaAs layer could be grown by addition of AlCl3 to GaCl3 in GaAs ALE growth.