Applied Physics Letters · 1994 · 17 citations · 9 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsDopingMos CapacitorsSemiconductor Device MaterialsSemiconductor SurfacesSurface OxidationThin Film OxidationFixed Charge DensityMolecular Beam EpitaxyOxidationOxidation Defect FormationSelective OxidationSemiconductor OxidationSurface Oxidation MechanismsWet Oxidation
A 1 μm thick n-type GaAs layer with Si doping density of 1×1017/cm3 and a 1000 Å thick undoped AlAs layer was subsequently grown by molecular beam epitaxy on the n+ GaAs substrate. To perform selective oxidation of the AlAs layer, the wafer was oxidized in N2 bubbled H2O vapor ambient at 370 °C, 400 °C, and 430 °C, each for 3 hours. It is found that the defect-free selective oxidation of AlAs is very critically dependent on oxidation temperature. Both GaAs and AlAs layers were oxidized at the oxidation temperature of 430 °C, and some defects were found by scanning electron microscopy (SEM) on the surface oxidized at 370 °C. Oxidation was, however, stopped at the AlAs/GaAs interface at the oxidation temperature of 400 °C, and no defects were found on the surface. By the slow ramp rate (5 mV/sec) high frequency (100 kHz) C-V measurement, the fixed charge density was estimated to be about 1×1011/cm2 for the metal-oxide-semiconductor (MOS) capacitor fabricated from the oxidized sample at 400 °C.
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GaAs Oxidation and the Ga‐As‐O Equilibrium Phase Diagram
C. D. Thurmond, G. P. Schwartz, G. W. Kammlott et al. · Journal of The Electrochemical Society · 1980 · 199 citations