Effects of active hydrogen on atomic layer epitaxy of GaAs

Atomic layer epitaxy of GaAs employing thermally activated hydrogen molecules is reported. It is found that hydrogen molecules thermally activated in a high-temperature cell reduce the ALE temperature, while the activation energy of formation of the methyl–Ga surface from the As surface does not change. On the other hand, the activation energy of formation of the As surface from the methyl–Ga surface remarkably decreases in the active hydrogen flow, indicating that AsH3 molecules dissociate into AsHx (x=1 or 2) in the vapor phase.