Pure Gd2O3 Research Articles

Characteristics of Ga2O3(Gd2O3)/GaAs interface: Structures and compositions

Growth of a single crystal was found in the first few oxide layers on GaAs(100) substrate, electron beam evaporated from a Ga5Gd3O12 source. Reflection high-energy electron diffraction and x-ray diffraction studies show that the thin oxide film is epitaxially grown on GaAs with the surface normal (110) and in-plane axis [001] parallel to (100) and [011] of GaAs, respectively, and the crystallographic structure is isomorphic to Mn2O3. The chemical composition of the oxide film was determined by x-ray photoelectron spectroscopy to be unequivocally pure Gd2O3. Based on Gibbs free energies of formation for all possible pairs in Ga, As, Gd, and O, a model is proposed to explain the epitaxy and the growth of single-domain Gd2O3 on GaAs.

Initial growth of Ga2O3(Gd2O3) on GaAs: Key to the attainment of a low interfacial density of states

Growth of the first few layers of an oxide mixture Ga2O3(Gd2O3) on GaAs (100) substrate, electron-beam evaporated from a Ga5Go3O12 source, was found to be a single crystal. Reflection high-energy electron diffraction and x-ray diffraction studies show that the thin oxide film is epitaxially grown on GaAs with the surface normal (110) and in-plane axis [001] parallel to (100) and [011] of GaAs, respectively, and has a structure isomorphic to Mn2O3. Studies using high-resolution transmission electron microscopy on the oxide–GaAs interface indicate some atomic registry between the oxide and GaAs during the initial growth. The chemical composition of the oxide film was determined by x-ray photoelectron spectroscopy to be unequivocally pure Gd2O3.

The (Ga2O3)1−x(Gd2O3)x, Oxides with x = 0–1.0 for GaAs Passivation

ABSTRACTGa2O3(Gd2O3) film was previously discovered to effectively passivate GaAs surface, and the employment of this oxide as gate dielectric has led to the first demonstration of the enhancement-mode GaAs metal oxide semiconductor field effect transistors (MOSFETs) with inversion. In order to gain insight into the passivation mechanism and elucidate the role of Gd2O3, we have carried out a systematic study of the dependence of the structural and dielectric properties of (Ga2O3)1−x(Gd2O3) on the Gd (x) content. Our studies indicate that it is necessary to have the Gd addition exceeding 14% in order to form an electrically insulating dielectric with low interfacial state density. Furthermore, we found that pure Gd2O3 film grows epitaxially on GaAs in the single domain, (110) oriented Mn2O3 structure. This new crystalline dielectric has a dielectric constant ∼10, and shows excellent dielectric properties with low leakage and high breakdown strength even for films as thin as 2.5 nm. We expect that epitaxial growth of the Mn2O3 structure can be extended to other rare earth oxides, and to other semiconductor substrates like Si.