Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena · 1983 · 36 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor MaterialsSurface SciencePhotoelectrochemical MaterialsSemiconductor Device MaterialsSemiconductor InterfacesSemiconductor SurfacesSurface PassivationX-ray Photoelectron SpectroscopyGallium ArsenidePassivation LayersPassivation MechanismsPassivation Of SemiconductorsPassivation TechniquesPhotochemical PassivationSemiconductor Surface PreparationWet Chemical Etching
A wet chemical technique is described for passivating air-exposed GaAs surfaces. The passivating layer is elemental arsenic which forms as a result of illuminating an n-type GaAs wafer immersed in a mixture of HCl acid and deionized 18 MΩ water with light from a mercury vapor lamp at intensities of 0.01–0.05 W-cm−2. Studies using XPS, LEED, and UPS show that the passivated surfaces have the following properties: (1) there is little or no Ga or Ga and As oxide species in the As film or at the film/GaAs interface; (2) a strong GaAs LEED pattern is observed after a 290 °C anneal following low energy ion beam bombardment. This suggests that the As/GaAs interface formed by photoetching is free of contaminates and that the GaAs surface is well ordered prior to ion bombardment or heat treatment. Thus, clean, well ordered surface of GaAs which have been previously air exposed can now be obtained at lower temperatures than previously. This creates new possibilities for surface studies, epitaxy, and metallization.