Rare-earth oxide thin films for gate dielectrics in microelectronics

Leskelä, Markku; Kukli, Kaupo; Ritala, Mikko

doi:10.1016/j.jallcom.2005.10.061

Cited by 144 publications

(96 citation statements)

References 101 publications

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“…The experimental PI-TOF mass spectrum suggests the reaction pathway of La(Cp) 3 → La(Cp) 2 + Cp → La(Cp) + 2 Cp → La 0 + 3 Cp, with neutral Cp ligand ejection through laser excitation into the LMCT states. In Figure 7 all simulated mass spectra clearly show features of La(Cp) 3 + , La(Cp) 2 + , and La(Cp) + . It is observed that relative peak intensities in the calculated mass spectra depend on the excitation energy.…”

Section: Resultsmentioning

confidence: 96%

Photoinduced Charge Transfer versus Fragmentation Pathways in Lanthanum Cyclopentadienyl Complexes

Han

Meng

Rasulev

et al. 2017

J. Chem. Theory Comput.

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This study compares two competing pathways of photoexcitations in gas-phase metal−organic complexes: first, a sequence of phonon-assisted electronic transitions leading to dissipation of the energy of photoexcitations and, second, a sequence of light-driven electronic transitions leading to photolysis. Phonon-assisted charge carrier dynamics is investigated by combination of the density matrix formalism and on-the-fly nonadiabatic couplings. Light-driven fragmentation is modeled by a time-dependent excited-state molecular-dynamics (TDESMD) algorithm based on Rabi theory and principles similar to the trajectory surface hopping approximation. Numerical results indicate that, under the medium intensity of the laser field, lightdriven electronic transitions are more probable than phonon-assisted ones. The formation of multiple products is observed in TDESMD trajectories. Simulated mass spectra are extracted from TDESMD simulations and compared to experimental photoionization time-of-flight (PI-TOF) mass spectra. It is found that several features in the experimental mass spectra are reproduced by the simulations.

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Section: Resultsmentioning

confidence: 96%

Photoinduced Charge Transfer versus Fragmentation Pathways in Lanthanum Cyclopentadienyl Complexes

Han

Meng

Rasulev

et al. 2017

J. Chem. Theory Comput.

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“…REOs are attractive because there is a compromise between the energy gap and k, so as to combine good insulating properties with potential for oxide scaling. La 2 O 3 [12][13][14][15], Y 2 O 3 [16][17][18][19], and CeO 2 [20][21][22] are the examples of REO, which have been deposited on Si substrate.…”

Section: Introductionmentioning

confidence: 99%

Effects of post-deposition annealing temperature and time on physical properties of metal-organic decomposed lanthanum cerium oxide thin film

2011

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“…TDESMD calculations were performed on the entire Ln(iCp) 3 model for a duration up to 2 ps, illustrating mostly intact ligand ejection with some minor cracking including hydrogen abstraction. TDESMD was also initiated starting from intermediate Ln(iCp) 2 and Ln(iCp) models, from which extensive ligand cracking could be observed. Additional simulations were performed, starting from [Ln(iCp) − H] and [Ln(iCp) − CH 3 ], analogues to the products of reactions 2 and 3, as well as for several other intermediates, as will be discussed below.…”

Section: Introductionmentioning

confidence: 99%

“…We have divided that subsection into 3.2(i) with an overview of the mass spectrum of the cracked fragments, 3.2(ii) on the hydrogen abstraction mechanism, 3.2(iii) on the methyl abstraction, 3.2(iv) on the isopropyl abstraction and cross-links from the other pathways, and 3.2(v) on additional reactions subsequent to hydrogen abstraction. The reaction mechanisms described in 3.2(ii)−(v) all invoke interligand abstraction and thus must start with Ln(iCp) 2 3 (99.9% Tb) were purchased from Strem Chemicals. All chemicals were used with no further purification, and were kept inside a glovebox in an argon atmosphere before use.…”

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confidence: 99%

Photofragmentation Pathways for Gas-Phase Lanthanide Tris(isopropylcyclopentadienyl) Complexes

et al. 2016

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Photofragmentation mechanisms of gas-phase lanthanide tris-(isopropylcyclopentadienyl) complexes, Ln(iCp) 3 , were studied through experimental photoionization time-of-flight mass spectrometry (PI-TOF-MS). A DFTbased time-dependent excited-state molecular dynamics (TDESMD) algorithm, under standard approximations, was used to simulate the photofragmentation process. Two competing reaction pathways, intact ligand stripping and ligand cracking within the metal−ligand complex, were hypothesized based on experimental data. It was evident that intramolecular hydrogen, methyl, and isopropyl abstraction play an important role in the ligand-cracking reaction pathway, leading to metal carbide and metal hydrocarbide products. The TDESMD simulations also produced branching reaction pathways for ligand ejection and ligand cracking and further suggested that both pathways are initiated by ligand-to-metal charge transfer. Although the simulations reproduced several of the proposed reactions and several of the products of cracking observed in the PI-TOF mass spectra, differences between the simulation and experimental results suggest specific directions for improvement in the computational model.

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Rare-earth oxide thin films for gate dielectrics in microelectronics

Cited by 144 publications

References 101 publications

Photoinduced Charge Transfer versus Fragmentation Pathways in Lanthanum Cyclopentadienyl Complexes

Photoinduced Charge Transfer versus Fragmentation Pathways in Lanthanum Cyclopentadienyl Complexes

Effects of post-deposition annealing temperature and time on physical properties of metal-organic decomposed lanthanum cerium oxide thin film

Photofragmentation Pathways for Gas-Phase Lanthanide Tris(isopropylcyclopentadienyl) Complexes

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