| 61. |
- Hu, Hanmei, et al.
(författare)
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Solvothermal synthesis of Sb2S3 nanowires on a large scale
- 2003
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Ingår i: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 258:1-2, s. 106-112
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Tidskriftsartikel (refereegranskat)abstract
- Sb2S3 nanowires with high aspect ratios have been successfully prepared on a large scale using SbCl3 and Na2S as starting materials in ethylene glycol at 200°C for 10 h. Field emission scanning electron microscopy images and transmission electron microscopy images show that the nanowires have diameters in the range of 20–100 nm and lengths up to 50 μm. Diffuse reflection spectrum indicates that the as-prepared Sb2S3 nanowires have obvious quantum size effects. The effects of reaction parameters on the growth of nanowires were discussed. A possible mechanism on the formation of the Sb2S3 nanowires was proposed.
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| 62. |
- Huang, D. G., et al.
(författare)
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Synthesis, structural characterizations and magnetic properties of a series of mono-, di- and polynuclear manganese pyridinecarboxylate compounds
- 2004
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :7, s. 1454-1464
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Tidskriftsartikel (refereegranskat)abstract
- Seven new manganese(II, III, IV) pyridinecarboxylate compounds (Et4N)[MnCl2(pic)(2)] (1, Hpic = picolinic acid) [MnCl(Pic)(2)(H2O)].H2O (2), [MnCl(pic)(H2O)2](n) (3), [Mn(Pic)(2)](n) (4), [MnCl(pic)](n) (5), [MnCl2(4-C5H4NHCOO)](n) (6) and [Mn2O2(pic)(4)] (7) were synthesized and structurally characterized. The picolinate ligand coordinates to the Mn ion forming a chelating five-membered ring which constructs diverse architectures by various bridging modes, such as mu-Cl, mu(1,1)(-) and mu(1,3)-carboxylate bridges (syn-syn and syn-anti modes). The interaction between the pyridyl rings is discussed, displaying a face-to-face pi-pi stacking for complex 6 and a T-shaped C-H...pi attraction for complex 4. Complex 3 has an infinite zigzag chain structure in which two neighboring Mn ions are linked by a carboxylate bridge in a syn-anti mode. In complex 4, the Mn(pic)(2) fragments are joined to each other by double mu(1,1)-carboxylate bridges, forming a 2D layer structure. Complex 5 contains Mn4O4 square subunits which are connected by double mu-Cl bridges to form a grid-like 2D structure. The isonicotinate complex 6 has a zigzag chain structure containing mixed double mu-Cl and mu(1,3)-carboxylate bridges in a syn-syn mode. Protonation at the pyridyl-N position was found and identified by the IR and magnetic properties of 6. The participation of an oxidizing agent like MnO4- leads to complexes containing higher valent manganese (1, 2 and 7). The IR spectra of these complexes are discussed and found to be consistent with the structural features. The magnetic properties of complexes 4, 5 and 6 have been investigated. Antiferromagnetic coupling interactions were observed and satisfactory fitting results were obtained with J values ranging from -0.63 cm(-1) to -2.35 cm(-1). The magnetic parameters of these complexes, together with the parameters of other Mn complexes with comparable structures, are compared and discussed based on the bridging modes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
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| 63. |
- Huang, D. U., et al.
(författare)
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Synthesis, structural characterization and magnetic properties of 2-pyrazinecarboxylate manganese compounds Mn(pyz)(2)(H2O)(4) and MnCl(pyz)(H2O) (n) (pyz=2-pyrazinecarboxylate)
- 2003
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Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 353, s. 284-291
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Tidskriftsartikel (refereegranskat)abstract
- Two pyz complexes [Mn(pyz)(2)(H2O)(4)] (1) and [MnCl(pyz)(H2O)] (2) have been synthesized and structurally characterized. Complex 1 contains an eight-coordinate Mn(II) ion with square anti-prismatic geometry. The extensive intermolecular hydrogen-bonding interactions of O-carboxyl...H-O-aqua correlate the complex molecules, forming 2D polymeric layer structure. The structure of complex 2 contains 1D Mn/pyz chains, which link to each other by double mu(2)-Cl bridges to form 2D layer with Mn...Mn distance of 3.664 Angstrom. Hydrogen-bonding interactions of O-carboxyl...H-O-aqua are found between the layers to correlate the 2D layers to form a 3D framework. In addition, the variable temperature magnetic susceptibilities of complex 2 were measured and weak ferromagnetic exchange interactions between the neighboring magnetic species were found with J = 0.42 cm(-1).
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| 64. |
- Hållstedt, Julius., et al.
(författare)
-
Strain and electrical characterization of boron-doped SiGeC layers grown by chemical vapor deposition
- 2004
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T114, s. 31-33
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Tidskriftsartikel (refereegranskat)abstract
- Incorporation, induced strain and electrical properties of boron and carbon in Si1-x-yGexCy epitaxial layers (x = 0.23 and 0.28 with y = 0 and 0.005) grown by chemical vapour deposition (CVD) have been studied. The boron concentration in the epitaxial layers was in the range of 3 x 10(18)-1 x 10(21) cm(-3). The growth rate enhanced weakly by increasing boron partial pressure up to 0.002 mtorr ( corresponding to 2 x 10(19) cm(-3)) where a significant increase in deposition rate was observed. In SiGeC layers, the active boron concentration was obtained from the strain compensation amount. It was also found that the boron atoms have a tendency to locate at substitutional sites more preferentially compared to carbon. The incorporation of boron in SiGeC layers was clearly improved in the range 2 x 10(19)-3 x 10(20) cm(-3). These investigations also enabled an estimation of the Hall scattering factor of the SiGeC layers. A comparison between our results with the previous theoretical calculations showed a good agreement. This created the possibility to evaluate the drift mobility in our samples.
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| 65. |
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| 66. |
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| 67. |
- Isheden, Christian, et al.
(författare)
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Formation of Ni mono-germanosilicide on heavily B-doped epitaxial SiGe for ultra-shallow source/drain contacts
- 2003
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Ingår i: Materials Research Society Symposium Proceedings. - 0272-9172 .- 1946-4274. ; 745, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- The formation of Ni germanosilicides during solid-state interaction between Ni and heavily B-doped strained epitaxial Si1-xGex films with x=0.18, 0.32 and 0.37 is studied. No NiSi2 is found in these samples even after annealing at 850 degreesC, which can be compared to the formation of NiSi2 at 750 T on Si(I 00). Resistance and diffraction studies for the Si0.82Ge0.18 sample indicate that NiSi0.82Ge0.18 forms and the NiSi0.82Ge0.18/Si0.82Ge0.18 structure is stable from 400 to 700 degreesC. For the NiSi1-uGeu formed in all Si1-xGex samples, where u can be different from x, a strong film texturing is observed. When the Ge fraction is increased from 18 at.% to 32-37 at.%, the morphological stability of the film is degraded and a substantial increase in sheet resistance occurs already at 600 degreesC. The contact resistivity for the NiSi0.8Ge0.2/Si0.8Ge0.2 interface formed at 550 T is determined as 1.2x10(-7) Omegacm(2), which satisfies the ITRS contact resistivity requirement for the 70 nm technology node.
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| 68. |
- Isheden, Christian, et al.
(författare)
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MOSFETs with recessed SiGe Source/Drain junctions formed by selective etching and growth
- 2004
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Ingår i: Electrochemical and solid-state letters. - : The Electrochemical Society. - 1099-0062 .- 1944-8775. ; 7:4, s. G53-G55
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Tidskriftsartikel (refereegranskat)abstract
- A source/drain extension process that uses HCl etching followed by selective growth of in situ B-doped SiGe is demonstrated. The two key process steps, etching and growth, are integrated by performing them consecutively in the same chemical vapor deposition reactor. The technique has the potential to solve end-of-the-roadmap requirements on junction depth, junction abruptness, and active doping concentration.
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| 69. |
- Isheden, Christian, et al.
(författare)
-
Selective Si etching using HCl vapor
- 2004
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T114, s. 107-109
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Tidskriftsartikel (refereegranskat)abstract
- Selective Si etching using HCl in a reduced pressure chemical vapor deposition reactor in the temperature range 800-1000 degrees C is investigated. At 900 degrees C, the etch process is anisotropic, exhibiting the densely packed (100), (311) and (111) surfaces. This behavior indicates that the etch process is limited by surface reaction, since the etch rate in the directions with higher atomic concentration is lower. When the temperature is decreased to 800 degrees C, etch pits occur. A more isotropic etch is obtained at 1000 degrees C, however at this temperature the masking oxide is attacked and the etch surface is rough. Thus the temperature has to be confined to a narrow window to yield desirable properties under the present process conditions.
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| 70. |
- Jarmar, T., et al.
(författare)
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Cross-sectional transmission electron microscopy study of the influence of niobium on the formation of titanium silicide in small-feature contacts
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:8, s. 4480-4484
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Tidskriftsartikel (refereegranskat)abstract
- The influence of a Nb layer between Si and Ti on the formation of TiSi2 in small-feature contacts and of the substrate doping level has been studied using transmission electron microscopy in combination with convergent-beam electron diffraction. For an As dose of 2.5x10(16) cm(-2), a mixture of C49 and partially agglomerated C54 TiSi2 grains was found in some of the 5x5 mum(2) contact windows, while only C49 existed in the 0.7x0.7 mum(2) windows. Agglomeration is shown to lead to possible C49-C54 coexistence, as well as erroneous interpretation of the C54 nucleation density. Decreasing the As dose to 5x10(15) cm(-2) leads to a thicker TiSi2 layer, but does not have a major influence on phase formation in the small windows, although only C54 TiSi2 was found in the large ones. In the presence of a thin Nb layer between Ti and poly-Si, C40 (Ti,Nb)Si-2 was consistently found in all contacts, indicating that formation does not depend on the contact size at least down to 0.5 mum(2). Surprisingly, Ti was found on both sides of the (Ti,Nb)Si-2 layer and the silicide near the interface to Si was relatively rich in Ti instead of Nb.
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