Surface Cleaning of AlGaAs Substrates by Hydrogen Electron Cyclotron Resonance (ECR) Plasma

Surface cleaning of AlGaAs substrates by hydrogen electron cyclotron resonance (ECR) plasma is carried out. Plasma is transported to the substrate surface by a divergent magnetic field. In situ reflection high-energy electron diffraction (RHEED) observation reveals that surface cleaning of AlGaAs can be successfully performed at a temperature as low as 500°C. From secondary ion mass spectrometry (SIMS) measurements, oxygen concentrations at the interface between the AlGaAs substrate and the GaAs layer grown after plasma cleaning are found to decrease as the substrate temperature decreases. At 500°C, flat surfaces with streaked RHEED patterns and clean interfaces with neither carbon nor oxygen accumulations can be obtained by hydrogen ECR plasma cleaning.