Photoelectrochemical passivation of GaAs surfaces
نویسندگان
چکیده
A wet. chemical techniq~e is ~escribed for passivating air-exposed GaAs surfaces. The passivating ~ayer IS elemental arsemc WhICh forms as a result of illuminating an n-type GaAs wafer immersed ~n a ~i~ture of Hel acid and d~ionized 18 Mil water with light from a mercury vapor lamp at mtenSltles of 0.01-0.05 yY-cm. Studies using XPS, LEBD, and UPS show that the passivated surfaces have the followmg 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 foHowing low energy ion beam bombardment. This suggests that the As/GaAs interface ~ormed by photoetching is free of contaminates and that the GaAs surface is well ordered prior to lOn 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,
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