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The effects of post-deposition annealing temperatures (600-1150°C) in 95%N-5%H ambient on the electrical and physical properties of metal-organic decomposed CeO spin-coated on n-type 4H-SiC were investigated. As the annealing temperature increased, oxides changed from polycrystalline to preferred oriented structures and, eventually, to silicate structures. The oxides also showed an incremental increase in surface roughness as annealing temperature increased. The Lorentz-Lorenz law was utilized to determine the density of the oxides. The highest density was obtained by a sample annealed at the highest temperature. Electrical results showed that this sample obtained the lowest leakage current density. Parameters affecting this observation were also investigated. [ABSTRACT FROM AUTHOR]

Cerium oxide (CeO2) solution was prepared by cerium(lIl) acetylacetonate hydrate, methanol, and acetic acid as the starting materials via the metallorganic decomposition (MOD) method. Postdeposition annealing was performed Onto the MODderived CeO2 films deposited onto ntype Si substrates at different temperatures (600, 800, and 1000°C) under the flow of argon gas. A slow cooling rate was then accomplished for samples to cool down to room temperature. Four orientations [III), (200), (220), and (311)] of CeO2 films were revealed by Xray diffraction analysis as well as csCe2O3 and cerium silicate (Ce2Si2O7). Epitaxiallike behavior was shown in the sample annealed at 600°C due to the (200)oriented CeO2 film, and the dominance of this plane ceased with the increase in annealing temperature. A negative voltage shift was observed in all of the samples, indicating that positive oxide charges were trapped in the oxide as a result of the presence of oxygen vacancies. An interface trap density was extracted from the capacitancevoltage measurement, and it was related to the current densityvoltage characteristics of the investigated samples. The lowest density was perceived by the sample annealed at 1000°C due to the increment in the Ce2Si2O7 layer, reduction in total interface trap density, and effective oxide charge. 0 [ABSTRACT FROM AUTHOR]

Abstract: Cerium oxide (CeO2) precursor, prepared by metal-organic decomposition method, was spin-coated on n-type 4H-SiC substrate. Effect of post-deposition annealing (600, 800, and 1000°C) in argon ambient on physical properties of the deposited film (∼110nm) was investigated. Refractive index (n f ) of the film was measured by ellipsometer. Lorentz–Lorenz law was applied to estimate the film density (ρ f ). n f and ρ f were increased with increasing annealing temperature. Film with defect-free surface had been revealed under field-emission scanning electron microscope. In order to study topography and surface roughness of the annealed oxides and SiC surfaces, atomic force microscope was used. The film showed an increment in surface roughness when the annealing temperature was increased. X-ray diffraction (XRD) was employed to detect the presence of crystalline phases and orientations in the films. Williamson–Hall plots were constructed from XRD line broadening, in which grain size (D) and microstrains were determined. Opposite relationship between D and microstrains was observed with the increase of annealing temperature. Coefficient of texture was calculated and used to measure preferred orientation of the film. All of the films annealed at different temperatures demonstrated (200)-preferred orientation. [Copyright &y& Elsevier]

Abstract: The utilization of metal-organic decomposed cerium oxide (CeO2) film as a gate oxide spin-coated on n-type GaN and SiC for metal-oxide-semiconductor structure has been investigated. Post-deposition annealing (PDA) in oxygen ambient at 1000°C was performed on both CeO2/GaN and CeO2/SiC systems while a higher PDA was carried out on CeO2/SiC system at 1150°C. The cross-sectional images of scanning transmission electron microscopy (STEM) and elemental line profiles of energy dispersive X-ray verified the formation of interfacial layer (IL) and its compound. It had been perceived from STEM that decomposition of GaN substrate during PDA at 1000°C had led to the crack formation on the surface of GaN and this issue was not confronted by the SiC substrate. From X-ray diffraction analysis all samples revealed CeO2 phase, but additional phase of α-Ce2O3 can only be detected by SiC and GaN with CeO2 annealed at 1150 and 1000°C, respectively. The transformation of phase might assist in the formation of IL between CeO2 and the substrate. A detailed comparison on the physical and electrical characteristics of the CeO2 gate deposited on both substrates was systematically presented. [Copyright &y& Elsevier]