Initial growth mechanism of atomic layer deposited titanium dioxide using cyclopentadienyl-type precursor: A density functional theory study

Zhou, Guangfen; Ren, Jie; Zhang, Shaowen

doi:10.1016/j.tsf.2012.09.046

Cited by 9 publications

(4 citation statements)

References 62 publications

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“…In order to investigate the ALD growth mechanisms of thin films, cluster models [20][21][22][23][24][25][26][27] and periodic slabs [28][29][30] have been extensively applied to simulate substrate surface in many theoretical studies. The results based on cluster models are in good agreement with experimental findings, showing that cluster models are quite reasonable.…”

Section: Computational Models and Methodsmentioning

confidence: 99%

“…The results based on cluster models are in good agreement with experimental findings, showing that cluster models are quite reasonable. In this work, a hydroxylated one-dimer cluster Si 9 H 12 [24][25][26][27] is employed to simulate Si(100)-2×1 surface. The Si 9 H 12 cluster consists of four layer Si atoms, in which the top two Si atoms compose the surface dimer and the other seven Si atoms compose three subsurface layers.…”

Section: Computational Models and Methodsmentioning

confidence: 99%

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Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO2 on H/Si(100)-2×1 Surface

Zhou

Ren

Zhang

2013

AMR

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The initial surface reaction mechanisms of atomic layer deposition TiO2on H/Si (100 )-2×1 surface using Ti (OCH3)4and H2O as precursors are investigated by density functional theory. The ALD process is divided into two half-reactions, i.e., Ti (OCH3)4and H2O half-reactions. The adsorption energy of Ti (OCH3)4on H/Si (100)2×1 surface is only-2.4 kJ/mol. The overall reaction of Ti (OCH3)4is exothermic, which indicates that Ti (OCH3)4half-reactions are favorable on thermodynamic. Howerver, H2O half-reactions are endothermic and thermodynamically unfavorable.

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Section: Computational Models and Methodsmentioning

confidence: 99%

Section: Computational Models and Methodsmentioning

confidence: 99%

Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO2 on H/Si(100)-2×1 Surface

Zhou

Ren

Zhang

2013

AMR

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“…In order to investigate the ALD growth mechanisms of thin films, cluster models [17][18][19][20][21][22][23][24] and periodic slabs [25][26][27] have been extensively applied to simulate silicon surface in many theoretical studies. The results based on cluster models are in good agreement with experimental findings, showing that cluster models are quite reasonable.…”

Section: Computational Models and Methodsmentioning

confidence: 99%

Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO2 Using Ti(OCH3)4 and H2O as Precursors

Zhou

Ren

Zhang

2013

AMR

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The initial surface reaction mechanisms of atomic layer depositionTiO2using Ti (OCH3)4and H2O as the precursors are investigated by density functional theory. The ALD process is divided into two half-reactions, i.e., Ti (OCH3)4and H2O half-reactions. The adsorption of Ti (OCH3)4on OH/Si (100)2×1 surface is exothermic. However, the overall reaction of Ti (OCH3)4is endothermic. In addition, H2O half-reactions are endothermic and thermodynamically unfavorable.

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“…These precursors, however, sometimes have drawbacks such as halide contamination and low stabilities in the case of the halide and alkoxides, respectively. Consequently, heteroleptic precursors including more than one type of ligands such as cyclopentadienyl (Cp)-alkoxides and Cp-alkylamides are developed, to enhance the thermal stability of precursors of the ALD high-k oxides. − When ozone is used as the oxygen source, ALD using zirconium and hafnium Cp-alkylamide precursors shows high growth per cycle (GPC), ranging from 0.8 to 0.9 Å per cycle, and the deposited films mostly possessed low levels of nitrogen and carbon contamination. Especially, ZrO 2 and HfO 2 films deposited using CpZr(N(Me 2 ) 3 and CpHf(N(Me 2 ) 3 precursors (Me = CH 3 ) and ozone have shown improved film density and electrical performance, possibly due to the deposition temperatures being as high as 350 °C.…”

Section: Introductionmentioning

confidence: 99%

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

et al. 2022

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Deposition of high-k dielectric thin films is essential for manufacturing modern electronic devices. Atomic layer deposition (ALD) is an attractive technology for depositing high-k materials because it exhibits conformality and facilitates thickness control of the films at the atomic level. It has been suggested that high-temperature ALD can enhance the material properties of the deposited films such as density and crystallinity, for which the development of thermally stable precursors that deliver the metallic element is required. Heteroleptic titanium (Ti), zirconium (Zr), and hafnium (Hf) precursors containing amido and cyclopentadienyl (Cp) ligands have recently been introduced, with some demonstrating improved thermal stability. However, the mechanism behind the improved thermal stability of these precursors remains unclear. This research employs density functional theory (DFT) calculations to elucidate the role of Cp ligands of group 4 (Ti, Zr, Hf) precursors for high-temperature ALD. The surface adsorption reactions of the precursors on oxide surfaces are suggested to be facile. For most precursors, one or two ligands are thought to exist after chemical adsorption. Cp ligands, in particular, are expected to persist on the surface, whereas amido ligands are more easily eliminated during adsorption. The decomposition of the precursor after adsorption on the surface then is considered, for which the thermal stability is significantly enhanced by introducing the Cp ligand. Furthermore, precursors with Cp ligands are more difficult to adsorb on the partially decomposed precursor-on-surface. Our findings intend to offer a fundamental molecular-level understanding of the thermal stability of group 4 precursors for high-temperature ALD.

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Initial growth mechanism of atomic layer deposited titanium dioxide using cyclopentadienyl-type precursor: A density functional theory study

Cited by 9 publications

References 62 publications

Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO<sub>2</sub><sub> </sub> on H/Si(100)-2×1 Surface

Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO<sub>2</sub><sub> </sub> on H/Si(100)-2×1 Surface

Initial Surface Reactions Mechanisms of Atomic Layer Deposition TiO<sub>2</sub><sub> </sub>Using Ti(OCH<sub>3</sub>)<sub>4</sub> and H<sub>2</sub>O as Precursors

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

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