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ABSTRACT: Energy-filtered transmission electron microscopy (EFTEM) was used to study 6H-SiC/SiO2 interfaces produced by thermal oxidation as a function of the oxidation conditions. Elemental maps of C and Si were used
to calculate C-to-Si concentration profiles across the interfaces. Enhanced C/Si concentrations (up to ∼ 35%) were observed
at distinct regions in samples oxidized at 1100°C for 4 h in a wet ambient. The data from a number of randomly selected regions
indicate that re-oxidation at 950°C for 3 h significantly reduced, but did not eliminate, the amount of excess interfacial
carbon.
Journal of Electronic Materials 04/2012; 32(5):464-469. · 1.47 Impact Factor
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ABSTRACT: High-resolution elemental profiles were obtained from SiO2(N)/4H‐SiC structures by spatially resolved electron energy-loss spectroscopy (EELS) performed in the scanning transmission electron microscopy mode. The results show that following annealing in NO, N was exclusively incorporated within ∼ 1 nm of the SiO2(N)/4H‐SiC interface. Mean interfacial nitrogen areal densities measured by EELS were ∼ (1.0±0.2)×1015 cm−2 in carbon-face samples and (0.35±0.13)×1015 cm−2 in Si-face samples; these results are consistent with nuclear reaction analysis measurements. Some of the interface regions in the C-face samples also showed excess carbon that was not removed by the NO annealing process, in contrast with previous results on Si-face samples.
Journal of Applied Physics. 05/2005; 97(10):104920-104920-6.
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ABSTRACT: Nitrogen incorporation at the SiO <sub>2</sub>/ SiC interface due to annealing in NO is measured and shown to be a strong function of crystal face. The annealing process involves two major solid-state chemical reactions: nitrogen uptake at the interface and N loss associated with second-order oxidation. An ad hoc kinetics model explains the experimental observations of anisotropy and nitrogen saturation.
Journal of Applied Physics 05/2005; · 2.17 Impact Factor
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ABSTRACT: In this study we investigated the morphology and interfacial chemistry of (0001) 4H-SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs) as a function of post-oxidation annealing in nitric oxide (NO) following wet oxidation. Energy-filtered transmission electron microscopy analyses showed enhanced C/Si concentrations (up to 13%) at distinct locations along the SiO2/SiC interface in the MOSFETs that were not annealed in NO. In contrast, regions of enhanced C/Si concentration were not detected in the MOSFETs that were annealed in NO; instead, these samples showed a trace amount of interfacial N. The introduction of N may therefore be associated with a reduction of C in these samples and may contribute to the higher channel mobility (∼38 cm2/V s) in the samples annealed in NO relative to the samples that were not annealed in NO (∼9 cm2/V s). Rough SiO2/4H-SiC interfaces and nonuniform oxide thickness were observed on both the NO- and the non-NO-annealed samples. The rough interfaces shown in the transmission electron microscopy bright field images may also be an important factor limiting the channel mobility in SiC-based MOSFETs. © 2004 American Institute of Physics.
Journal of Applied Physics 06/2004; 95(12):8252-8257. · 2.17 Impact Factor
