Structure and thermal stability of MOCVD ZrO2 films on Si (100)

Wu, Xiaohua; Landheer, D.; Graham, M. J.; Chen, H. W.; Huang, Tiao‐Yuan; Chao, Tien−Sheng

doi:10.1016/s0022-0248(03)00827-3

Cited by 27 publications

(5 citation statements)

References 13 publications

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“…Additionally, the spectra of the 800 and 900 °C samples exhibited two additional bands associated with the Si–O–Si bond, namely, the symmetric stretching vibration at ∼800 cm –1 and the longitudinal optical mode of ν as vibration at ∼1200 cm –1 as a shoulder of the TO mode. , It has been generally reported that the IL between the ZrO 2 layer and the Si substrate consists of zirconium silicate (Zr x Si 1– x O y ) and/or thermally grown silicon oxide (SiO x ). ,− Based on the development and variations of the bands relating to the Si–O–Si bond vibrations in the FTIR spectra, it was considered that the ILs of all of the samples had mainly the SiO x composition. This finding was also supported by the absence of the major band originating from the Si–O–Zr bond vibration, whose peak is generally centered at ∼950 cm –1 . , However, it cannot be completely excluded that a few-angstrom-thick zirconium silicate layer exists near the interface between the ZrO 2 and IL layers …”

Section: Resultsmentioning

confidence: 99%

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

et al. 2012

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Stabilization of high-temperature phases such as tetragonal (t-) or cubic phases has been a pivotal issue for technological applications of polymorphic ZrO2. In this work, we fabricated ZrO2/Si films using a sol–gel deposition route and investigated the phase transformation, microstructural evolution, surface morphological changes, and interfacial chemical structures by thermal annealing. The ZrO2 precursor solution was prepared using a zirconium acetylacetonate, coated, dried on Si substrates, and finally annealed at 300–950 °C in ambient air. The sol–gel-derived ZrO2 layer crystallized into the t-phase as the annealing temperature increased. Despite high-temperature annealing, the t-phase was stabilized without a noticeable transition to the monoclinic phase, probably because of the relatively low film thickness (∼15 nm), enlarged surface/interface area due to thermal grooving, and strain effects. The probable t(112) orientation was developed after annealing at ≥800 °C, which could be related to minimization of the sum of the surface, interface, and strain energies. High-temperature thermal annealing resulted in the contraction of the ZrO2 layer as a result of the pyrolysis of the remnant organics, surface roughening by thermal grooving, and thickening of the amorphous interface layer (predominantly SiO x ) between the ZrO2 and Si.

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Section: Resultsmentioning

confidence: 99%

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

et al. 2012

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“…In thin ZrO 2 films, the tetragonal polymorph, rather than the low-temperature equilibrium monoclinic phase, is often observed [46,47]. Possible reasons include high concentrations of oxygen vacancies or the small grain size of the films, because for the monoclinic phase to be stable, the grain size has to be greater than a critical value [48].…”

Section: B) High-k Oxygen Deficiencymentioning

confidence: 99%

Thermodynamic considerations in the stability of binary oxides for alternative gate dielectrics in complementary metal–oxide–semiconductors

Stemmer¹

2004

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

111

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A number of binary oxides have been predicted to be thermodynamically stable in contact with Si and are candidates to replace SiO 2 in CMOS. However, reactions leading to the formation of interfacial silicide, silicate or SiO 2 layers have been reported when these oxides are exposed to high temperatures during device processing. Different pathways have been proposed in the literature to explain these reactions. In this paper, a thermodynamic analysis of the proposed reactions is performed. The analysis includes gaseous species, because typical gate dielectrics are ultra-thin layers and diffusivities for species from the surrounding atmosphere, such as oxygen, may be high. Furthermore, nonstoichiometry of the high-k oxide, as may be resulting from nonequilibrium deposition processes or reducing atmospheres during processing is also considered. Studies are proposed to distinguish between possible reaction mechanisms. Finally guidelines for stable interfaces are presented.3

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“…4d). It has been reported that the chemical composition of the IL is Zr silicate (Zr x Si 1-x O y ) and/or Si oxide (SiO x ) [36,37]. The IL growth was possibly responsible for the development of the Si-O bond-related bands observed in the FTIR spectra with increasing annealing temperature.…”

Section: Methodsmentioning

confidence: 99%

Phase and structural evolution of sol–gel synthesized ZrO2/Si thin films under heat treatment

et al. 2012

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ZrO 2 /Si thin films were fabricated using a solgel technique, and the chemical state change and structural evolution from sol to gel to Zr oxide by heat treatment were investigated. The precursor sol was synthesized using a Zr-acetylacetonate (Zr-acac) precursor, spin-coated, dried on Si(100) substrates, and then annealed at 300-700°C in air. With increased annealing temperature of the sol-gelderived layer, Zr-acac decomposed into Zr-acetate, an amorphous ZrO 2 phase formed, and crystallization into a tetragonal phase occurred. In addition, the ZrO 2 layer became denser and the interfacial layer between ZrO 2 and Si thickened, whereas the surface morphology was nearly unaffected and remained smooth with root-mean-square values \ 4.5 Å .

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Structure and thermal stability of MOCVD ZrO2 films on Si (100)

Cited by 27 publications

References 13 publications

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

Thermodynamic considerations in the stability of binary oxides for alternative gate dielectrics in complementary metal–oxide–semiconductors

Phase and structural evolution of sol–gel synthesized ZrO2/Si thin films under heat treatment

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Structure and thermal stability of MOCVD ZrO2 films on Si (100)

Cited by 27 publications

References 13 publications

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO2/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO2/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

Thermodynamic considerations in the stability of binary oxides for alternative gate dielectrics in complementary metal–oxide–semiconductors

Phase and structural evolution of sol–gel synthesized ZrO2/Si thin films under heat treatment

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Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase

Phase Transition and Microstructural Changes of Sol–Gel Derived ZrO₂/Si Films by Thermal Annealing: Possible Stability of Tetragonal Phase without Transition to Monoclinic Phase