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| 2. |
- Sawkar-Mathur, Monica, et al.
(författare)
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The effect of aluminum oxide incorporation on the material and electrical properties of hafnium oxide on Ge
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:23, s. 233501-
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Tidskriftsartikel (refereegranskat)abstract
- Hafnium aluminate thin films were synthesized by atomic layer deposition (ALD) to assess the effect of aluminum oxide incorporation on the dielectric/Ge interfacial properties. In these HfxAlyOz thin films, the Hf to Al cation ratio was effectively controlled by changing the ratio of hafnium oxide to aluminum oxide ALD cycles, while their short range order was changed upon increasing aluminum oxide incorporation, as observed by extended x-ray absorption fine structure analysis. The incorporation of aluminum oxide was shown to improve the electrical characteristics of hafnium oxide/Ge devices, including lower interface state densities and leakage current densities.
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| 3. |
- Tanner, Carey M, et al.
(författare)
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Engineering epitaxial gamma-Al2O3 gate dielectric films on 4H-SiC
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 102:10, s. 104112-104112-6
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Tidskriftsartikel (refereegranskat)abstract
- The formation of epitaxial gamma-Al2O3 thin films on 4H-SiC was found to be strongly dependent on the film thickness. An abrupt interface was observed in films up to 200 A thick with an epitaxial relationship of gamma-Al2O3(111)parallel to 4H-SiC(0001) and gamma-Al2O3(4 (4) over bar0)parallel to 4H-SiC(11 (2) over bar0). The in-plane alignment between the film and the substrate is nearly complete for gamma-Al2O3 films up to 115 A thick, but quickly diminishes in thicker films. The films are found to be slightly strained laterally in tension; the strain increases with thickness and then decreases in films thicker than 200 A, indicating strain relaxation which is accompanied by increased misorientation. By controlling the structure of ultrathin Al2O3 films, metal-oxide-semiconductor capacitors with Al2O3 gate dielectrics on 4H-SiC were found to have a very low leakage current density, suggesting suitability of Al2O3 for SiC device integration.
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| 4. |
- Tanner, C. M., et al.
(författare)
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Structural properties of epitaxial gamma-Al2O3(111) thin films on 4H-SiC(0001)
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:6
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Tidskriftsartikel (refereegranskat)abstract
- Al2 O3 thin films were grown on 4H-SiC (0001) by thermal atomic layer deposition and were crystallized to the γ- Al2 O3 phase by rapid thermal annealing in N2 at 1100 °C. The films were found to be chemically stable during processing based on x-ray photoelectron spectroscopy. The change in film structure was initially confirmed by reflection high-energy electron diffraction. As shown by high-resolution transmission electron microscopy images, the abrupt interface of the as-deposited films with the 4H-SiC substrate was preserved during crystallization, indicating no interfacial reaction. Selected area electron diffraction and synchrotron-based x-ray diffraction established an epitaxial relationship of γ- Al2 O3 (111) ∥ 4H-SiC (0001) and in-plane orientation of γ- Al2 O3 (1 1- 0) ∥ 4H-SiC (11 2- 0). No other alumina phases or orientations were observed and no in-plane misorientation was observed in the 27 Å Al2 O3 films. The full width at half maximum of the γ- Al2 O3 (222) rocking curve is 0.056°, indicating a lack of mosaic spread and a high-quality crystalline film. Twinning around the γ- Al2 O3 [111] axis was the only defect observed in these films.
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