Interfacial reactions of Gd- and Nb-oxide based high-k layers deposited by aqueous chemical solution deposition

Dewulf, Daan; Peys, Nick; Elshocht, Sven Van; Rampelberg, Geert; Detavernier, Christophe; Gendt, Stefan De; Hardy, An; Bael, Marlies K. Van

doi:10.1016/j.mee.2011.03.045

Cited by 5 publications

(6 citation statements)

References 24 publications

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“…18,27 Therefore citrate is added to the solution as an α-hydroxy-carboxylato, cross-linking complexing agent. [34][35][36] Two different solutions are studied: (i) an aqueous citrato-oxalato-VO 2+ precursor, in which the oxalate groups remain in the solution and (ii) a citrato-VO 2+ solution whereby the oxalate groups are removed from the solution. In both solutions, the VO 2+ and citrate concentration equals 0.1 M and 0.2 M, respectively.…”

Section: Synthesis Of the Citrato(-oxalato)-vo 2+ Precursor Solutionmentioning

confidence: 99%

Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis

et al. 2014

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An aqueous precursor solution, containing citrato-VO(2+) complexes, is synthesized for the formation of monoclinic VO2. With regard to the decomposition of the VO(2+) complexes towards vanadium oxide formation, it is important to gain insights into the chemical structure and transformations of the precursor during synthesis and thermal treatment. Hence, the conversion of the cyclic [V4O12](4-) ion to the VO(2+) ion in aqueous solution, using oxalic acid as an acidifier and a reducing agent, is studied by (51)Vanadium nuclear magnetic resonance spectroscopy. The citrate complexation of this VO(2+) ion and the differentiation between a solution containing citrato-oxalato-VO(2+) and citrato-VO(2+) complexes are studied by electron paramagnetic resonance and Fourier transform infra-red spectroscopy. In both solutions, the VO(2+) containing complex is mononuclear and has a distorted octahedral geometry with a fourfold R-CO2(-) ligation at the equatorial positions and likely a fifth R-CO2(-) ligation at the axial position. Small differences in the thermal decomposition pathway between the gel containing citrato-oxalato-VO(2+) complexes and the oxalate-free gel containing citrato-VO(2+) complexes are observed between 150 and 200 °C in air and are assigned to the presence of (NH4)2C2O4 in the citrato-oxalato-VO(2+) solution. Both precursor solutions are successfully used for the formation of crystalline vanadium oxide nanostructures on SiO2, after thermal annealing at 500 °C in a 0.1% O2 atmosphere. However, the citrato-oxalato-VO(2+) and the oxalate-free citrato-VO(2+) solution result in the formation of monoclinic V6O13 and monoclinic VO2, respectively.

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Section: Synthesis Of the Citrato(-oxalato)-vo 2+ Precursor Solutionmentioning

confidence: 99%

Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis

et al. 2014

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“…The instability of Gd 2 O 3 against silicate formation on Si substrates has already been reported. 37,38 This low temperature silicate formation could be interesting for device applications, in order to keep SiO 2 -like properties while having Gd 2 O 3 -like permittivities, as was thoroughly studied in the HfSiON system. [39][40][41] The presence of a top poly-Gd 2 O 3 agrees with XRD results, suggesting that before FGA the sample was polycrystalline.…”

Section: A Structural Characterizationmentioning

confidence: 99%

Optimization of gadolinium oxide growth deposited on Si by high pressure sputtering

Feijoo

Pampillón

Andrés

2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Articles you may be interested inOptimization of in situ plasma oxidation of metallic gadolinium thin films deposited by high pressure sputtering on silicon J.Embedded argon as a tool for sampling local structure in thin plasma deposited aluminum oxide films Structural, optical, and electrical characterization of gadolinium oxide films deposited by low-pressure metalorganic chemical vapor deposition High j gadolinium oxide thin layers were deposited on silicon by high-pressure sputtering (HPS). In order to optimize the properties for microelectronics applications, different deposition conditions were used. Ti (scavenger) and Pt (nonreactive) were e-beam evaporated to fabricate metal-insulator-semiconductor (MIS) devices. According to x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, polycrystalline stoichiometric Gd 2 O 3 films were obtained by HPS. The growth rate decreases when increasing the deposition pressure. For relatively thick films (40 nm), a SiO x interface as well as the formation of a silicate layer (GdSiO x ) is observed. For thinner films, in Ti gated devices the SiO x interface disappears but the silicate layer extends over the whole thickness of the gadolinium oxide film. These MIS devices present lower equivalent oxide thicknesses than Pt gated devices due to interface scavenging. The density of interfacial defects D it is found to decrease with deposition pressure, showing a reduced plasma damage of the substrate surface for higher pressures. MIS with the dielectric deposited at higher pressures also present lower flatband voltage shifts DV FB in the C HF -V G hysteresis curves.

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“…TGA taken of the powders indicates that only a minor fraction of C containing residue stays behind after the 600 • C anneal. Higher anneal temperatures are avoided, because a higher anneal temperature on SiO 2 /Si substrates results in interlayer interactions between the deposited high-k layer and the SiO 2 /Si substrate, 38 To investigate the carbon containing residues left in the films after thermal treatment of 600 • C, GATR-FTIR is performed. Besides, GATR-FTIR also allows detection of metal oxides vibrations and silicate vibrations.…”

Section: Resultsmentioning

confidence: 99%

Gadolinium -niobates and -tantalates: Amorphous High-k Materials by Aqueous CSD

Dewulf

Hardy

Elshocht

et al. 2012

J. Electrochem. Soc.

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In this work, compositional series of Gd-Nb-oxides and Gd-Ta-oxides are investigated as new potential high-k materials. Ultrathin oxide films in the range of 5-25 nm are deposited by spincoating. XRD and AFM show that the films are amorphous and smooth (RMS < 1 nm). Dielectric constants are derived from capacitance voltage (CV) measurements and EOT extraction. K values of the Gd-Nb-Ox series range from 13-16 while higher k values are obtained for the Gd-Ta-Ox series ranging from 15-19. For the Gd-Nb-Ox series, a higher k value is obtained for the most Gd-rich composition, while the opposite trend for the Gd-Ta-Ox series is noticed. Furthermore, the Gd-Ta-Ox shows the lowest leakages, as concluded from current-voltage (IV) measurements. A higher Gd content leads to decreased leakage, concurrent with increased band gaps.

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Interfacial reactions of Gd- and Nb-oxide based high-k layers deposited by aqueous chemical solution deposition

Cited by 5 publications

References 24 publications

Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis

Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis

Optimization of gadolinium oxide growth deposited on Si by high pressure sputtering

Gadolinium -niobates and -tantalates: Amorphous High-k Materials by Aqueous CSD

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Interfacial reactions of Gd- and Nb-oxide based high-k layers deposited by aqueous chemical solution deposition

Cited by 5 publications

References 24 publications

Aqueous citrato-oxovanadate(iv) precursor solutions for VO2: synthesis, spectroscopic investigation and thermal analysis

Aqueous citrato-oxovanadate(iv) precursor solutions for VO2: synthesis, spectroscopic investigation and thermal analysis

Optimization of gadolinium oxide growth deposited on Si by high pressure sputtering

Gadolinium -niobates and -tantalates: Amorphous High-k Materials by Aqueous CSD

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Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis

Aqueous citrato-oxovanadate(iv) precursor solutions for VO₂: synthesis, spectroscopic investigation and thermal analysis