Growth and phase stabilization of HfO2 thin films by ALD using novel precursors

Niinistö, Jaakko; Mäntymäki, Miia; Kukli, Kaupo; Costelle, Leila; Puukilainen, Esa; Ritala, Mikko; Leskelä, Markku

doi:10.1016/j.jcrysgro.2009.10.028

Cited by 72 publications

(51 citation statements)

References 26 publications

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“…The monoclinic phase appeared to be dominant at this deposition temperature. The GI-XRD patterns obtained in this work are remarkably similar to the ones reported by Niinist€ o et al, 24 for the HfO 2 ALD process employing the same precursor, HfCp(NMe 2 ) 3 , and O 3 as the oxidizing agent. In their work, Niinist€ o et al showed a similar temperature dependence of the HfO 2 film crystallinity with a clear transition from amorphous to crystalline films at a deposition temperature of 300 C. The difference in temperature between this work and the one reported by Niinist€ o et al at which this transition could be observed is imputed to a $20%-25% difference between the set stage temperature value and the actual substrate temperature for the reactor employed in this work.…”

Section: B Optoelectronic Properties and Crystallinitysupporting

confidence: 87%

“…19 With the aim of combining the benefits of both precursor types, precursors comprising both cyclopentadienyl and alkylamide type ligands have been investigated. 23,24 A high thermal stability and high GPC attributed to cyclopentadienyl ligands and alkylamide ligands, respectively, have been demonstrated for both Hf and Zr based ALD processes. 23 24 The higher growth in the latter case might be attributed to the high reactivity of O 3 at a relatively low temperature resulting in the efficient removal of the bulky Cp ligands.…”

Section: Introductionmentioning

confidence: 99%

“…23,24 A high thermal stability and high GPC attributed to cyclopentadienyl ligands and alkylamide ligands, respectively, have been demonstrated for both Hf and Zr based ALD processes. 23 24 The higher growth in the latter case might be attributed to the high reactivity of O 3 at a relatively low temperature resulting in the efficient removal of the bulky Cp ligands. 24 However, both with H 2 O or O 3 as oxidizing agents, depositions have not been reported below 250 C, which might be necessary for HfO 2 film deposition on temperature-sensitive substrates, in particular, for organic device applications and flexible electronics based on novel nanomaterials.…”

Section: Introductionmentioning

confidence: 99%

“…23 24 The higher growth in the latter case might be attributed to the high reactivity of O 3 at a relatively low temperature resulting in the efficient removal of the bulky Cp ligands. 24 However, both with H 2 O or O 3 as oxidizing agents, depositions have not been reported below 250 C, which might be necessary for HfO 2 film deposition on temperature-sensitive substrates, in particular, for organic device applications and flexible electronics based on novel nanomaterials. 10,27 In this context, another alternative is to employ a plasma enhanced ALD process (i.e., O 2 plasma as oxygen source) in combination with the same Hf precursor [HfCp(NMe 2 ) 3 ] for growth of HfO 2 thin films.…”

Section: Introductionmentioning

confidence: 99%

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Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Sharma

Longo

Verheijen

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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HfO2 thin films were prepared by plasma-enhanced atomic layer deposition using a cyclopentadienyl-alkylamido precursor [HfCp(NMe2)3, HyALD™] and an O2 plasma over a temperature range of 150–400 °C at a growth per cycle around 1.1 Å/cycle. The high purity of the films was demonstrated by x-ray photoelectron spectroscopy and elastic recoil detection analyses which revealed that by increasing the deposition temperature from 200 to 400 °C, the atomic concentrations of residual carbon and hydrogen reduced from 1.0 to <0.5 at. % and 3.4 to 0.8 at. %, respectively. Moreover, Rutherford backscattering spectroscopy studies showed an improvement in stoichiometry of HfO2 thin films with the increase in deposition temperature, resulting in Hf/O ratio close to ∼0.5 at 400 °C. Furthermore, grazing incidence x-ray diffraction measurements detected a transition from amorphous at the deposition temperature of 300 °C to fully polycrystalline films at 400 °C, consisting of a mixture of monoclinic, tetragonal, and cubic phases. Finally, the surface morphology and conformality of HfO2 thin films studied by atomic force microscopy and transmission electron microscopy are also reported.

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Section: B Optoelectronic Properties and Crystallinitysupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Sharma

Longo

Verheijen

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…[20] The focus of this work is to evaluate the modified hafnium amide precursor, namely Hf-amide-guanidinate (1), for the ALD of HfO 2 in combination with water. To make a direct comparison of the ALD characteristics using compound 1 with respect to the parent hafnium amide compound 2, HfO 2 was grown using compound 2 under similar process conditions in the same reactor (ASM-F-120).…”

Section: Full Papermentioning

confidence: 99%

Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Milanov

Parala

et al. 2012

Chemical Vapor Deposition

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The application of a heteroleptic hafnium amide-guanidinate precursor for the deposition of HfO 2 thin films via a water-assisted atomic layer deposition (ALD) process is demonstrated for the first time. HfO 2 films are grown in the temperature range 100-300 8C using the compound [Hf(NMe 2 ) 2 (NMe 2 -Guan) 2 ] (1). This compound shows self-limiting ALD-type growth characteristics with growth rates of the order of 1.0-1.2 Å per cycle in the temperature range 100-225 8C. The saturation behavior and a linear dependence on film thickness as a function of number of cycles are verified at various temperatures within the ALD window. The as-deposited HfO 2 films are characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS), and electrical measurements. For a direct comparison of the precursor performance with that of the parent alkyl amide [Hf(NMe 2 ) 4 ] (2), ALD experiments are also performed employing compound 2 under similar process conditions, and in this case no typical ALD characteristics are observed.

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