Initial growth mechanisms of ZrO2 and TiO2 thin films using cycloheptatrienyl–cyclopentadienyl heteroleptic precursors: A comparative study by density functional theory

Zhou, Guangfen; Ren, Jie; Zhang, Shaowen

doi:10.1016/j.apsusc.2013.07.054

Cited by 4 publications

(4 citation statements)

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“…According to their report, all the investigated surfaces were reactive toward TiCl 4 , where different intermediate species with different activation barriers were formed on each surface [ 77 ]. Later on, DFT was employed to compare the initial growth mechanisms in ALD of TiO 2 and ZrO 2 on SiOH surfaces using cycloheptatrienyl (CHT)–cyclopentadienyl (Cp) precursors [ 170 , 172 ]. According to the authors’ DFT calculations, the reactions happened through similar pathways in both metal oxides, where one hydrogen atom from the surface was transferred to the precursor ligand ( Figure 7 , reprinted with permission from reference [ 170 ]).…”

Section: Theoretical Studies On Aldmentioning

confidence: 99%

“…Later on, DFT was employed to compare the initial growth mechanisms in ALD of TiO 2 and ZrO 2 on SiOH surfaces using cycloheptatrienyl (CHT)–cyclopentadienyl (Cp) precursors [ 170 , 172 ]. According to the authors’ DFT calculations, the reactions happened through similar pathways in both metal oxides, where one hydrogen atom from the surface was transferred to the precursor ligand ( Figure 7 , reprinted with permission from reference [ 170 ]). However, the Zr precursor adsorption was exothermic and thus energetically favorable, whereas that of the Ti precursor was endothermic and thermodynamically unfavorable.…”

Section: Theoretical Studies On Aldmentioning

confidence: 99%

“…However, the Zr precursor adsorption was exothermic and thus energetically favorable, whereas that of the Ti precursor was endothermic and thermodynamically unfavorable. The authors reported this difference to be a reason why an ALD window had been experimentally observed for ZrO 2 growth and not for TiO 2 growth [ 170 ]. The same researchers proposed initial reaction pathways for an ansa-metallocene Zr precursor ((Cp 2 CMe 2 )ZrMe 2 ), where the steric hindrance of the large ligand prevented the reaction from occurring through chemisorption, and it happened due to the dispersion effect of the bulky ligand [ 173 ].…”

Section: Theoretical Studies On Aldmentioning

confidence: 99%

“… Surface reactions of Cp Me Zr(CHT) and CpTi(CHT) on the SiOH surface (reprinted with permission from reference [ 170 ]). …”

Section: Figurementioning

confidence: 99%

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Recent Advances in Theoretical Development of Thermal Atomic Layer Deposition: A Review

et al. 2022

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Atomic layer deposition (ALD) is a vapor-phase deposition technique that has attracted increasing attention from both experimentalists and theoreticians in the last few decades. ALD is well-known to produce conformal, uniform, and pinhole-free thin films across the surface of substrates. Due to these advantages, ALD has found many engineering and biomedical applications. However, drawbacks of ALD should be considered. For example, the reaction mechanisms cannot be thoroughly understood through experiments. Moreover, ALD conditions such as materials, pulse and purge durations, and temperature should be optimized for every experiment. It is practically impossible to perform many experiments to find materials and deposition conditions that achieve a thin film with desired applications. Additionally, only existing materials can be tested experimentally, which are often expensive and hazardous, and their use should be minimized. To overcome ALD limitations, theoretical methods are beneficial and essential complements to experimental data. Recently, theoretical approaches have been reported to model, predict, and optimize different ALD aspects, such as materials, mechanisms, and deposition characteristics. Those methods can be validated using a different theoretical approach or a few knowledge-based experiments. This review focuses on recent computational advances in thermal ALD and discusses how theoretical methods can make experiments more efficient.

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