Abstract
Molecular beam epitaxy (MBE) grown high κ dielectric Al2O3 film on In0.2Ga0.8As/ GaAs substrate, has been demonstrated an effective passivation for InGaAs surface. Utilizing the high-temperature and room-temperature growth methods for the oxide deposition, both the MOS capacitors reveal excellent electrical properties and good thermal stability up to 800-850oC. A sharp oxide/semiconductor interface without the interfacial layer formation was observed by the high-resolution transmission electron microscope (HR-TEM) analysis. Well behaved capacitance-voltage (C-V) characteristics of the MOSCAPs after rapid thermal annealing (RTA) to 850 °C under helium ambience, with the κ value of 8.1, a leakage current density of 1.2x10-4 A/cm2 at Vfb -1V was obtained. From the ex-situ angular-resolved X-ray photoelectron spectroscopy analysis, there is no arsenic oxide, but extra elemental gallium is existed in the oxide films for the as-grown sample, this would be acted as an important factor to influence the C-V behavior. Moreover, the Fermi level at the oxide/InGaAs interface was unpinned, critical for inversion-channel InGaAs MOSFET.