GaAs epitaxial growth by a molecular beam epitaxy (MBE) equipment of VG Semicon V80H is presented. The Ga desorption rate during MBE growth on GaAs (n11)A (n=1 to 4) and (100) substrates was shown by photoluminescence (PL) measurements at 12 K for undoped AlGaAs/GaAs asymmetric double quantum wells. Reflection high energy electron diffraction oscillation measurement on a GaAs(100) surface was also used. With increasing As pressure, two separated PL peaks for the wide well of high index substrates were observed. This peak separation is attributed to a reduced well depth from an increasing Ga desorption rate. The increase of Ga desorption from the surface at high As pressures probably arose from an increasing coverage with a quasi-liquid layer (QLL). The interface morphology was also observed by a transmission electron microscopy. The mechanism of lateral wet oxidation of AlAs layers grown by MBE on GaAs substrates was studied for device application. The rate of the lateral oxidation depends on the Al composition and the AlAs layer thickness. Decreasing of the layer thickness of Al{sub}xO{sub}y to 94 of that of the original AlAs layer was measured by TEM.
展开▼
