Arsenic-free high-temperature surface cleaning of molecular beam epitxy (MBE)-grown AlGaAs layer with new passivation structure

To facilitate an MBE regrowth on an AlGaAs epilayer surface which is easily oxidized in the atmosphere, a passivation layer was provided on the top of the AlGaAs surface. This layer was either a GaAs single layer or a GaAs/ultra-thin AlGaAs/GaAs double-hetero (DH) structure layer grown at the final stage of the first MBE and it was sublimated during the arsenic-free high-temperature surface cleaning which was carried out at the first stage of MBE regrowth. The cleaned AlGaAs surface was examined by Auger electron spectroscopy. It exhibited an intensity ratio of oxygen to Al, Ga and As much lower for the DH passivated AlGaAs than for the AlGaAs passivated by a GaAs layer. Large electron mobility was systematically obtained for the high electron mobility structure grown on the cleaned AlGaAs. (C); 1999 Elsevier Science B.V. All rights reserved.