Atomic Layer Deposition of High‐<i>k</i> Oxides of the Group 4 Metals for Memory Applications

Niinistö, Jaakko; Kukli, Kaupo; Heikkilä, Mikko; Ritala, Mikko; Leskelä, Markku

doi:10.1002/adem.200800316

Cited by 132 publications

(83 citation statements)

References 84 publications

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“…2,[12][13][14][15] However, the limitations associated with this precursor, such as corrosive byproducts and poor nucleation on H-terminated Si at high temperatures (!300 C), make this precursor unfavorable for some specific applications like dynamic random-access memories and therefore have led for a search for alternative precursor chemistries. 2,15,16 One of such a widely applied alternative precursor group for HfO 2 ALD is alkylamide comprising metal-nitrogen bonds, namely Hf(NEtMe) 4 (TEMAH), Hf(NEt 2 ) 4 , and Hf(NMe 2 ) 4 (Et ¼ C 2 H 5 , Me ¼ CH 3 ). 3,[17][18][19][20] These alkylamide type precursors possess a high volatility and reactivity and yield a high growth per cycle (GPC) in combination with H 2 O or O 3 as coreactants.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…A wide range of applications exists for ALD, e.g., high-j oxides for CMOS and DRAM technology, 8,9 solar cell manufacturing, 10 catalysts, 11 and others. [12][13][14][15][16][17] In order to improve the control of the deposition process, several models for ALD have been published in recent years.…”

Section: Introductionmentioning

confidence: 99%

Modeling precursor diffusion and reaction of atomic layer deposition in porous structures

Keuter

Menzler

Mauer

et al. 2014

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

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Atomic layer deposition (ALD) is a technique for depositing thin films of materials with a precise thickness control and uniformity using the self-limitation of the underlying reactions. Usually, it is difficult to predict the result of the ALD process for given external parameters, e.g., the precursor exposure time or the size of the precursor molecules. Therefore, a deeper insight into ALD by modeling the process is needed to improve process control and to achieve more economical coatings. In this paper, a detailed, microscopic approach based on the model developed by Yanguas-Gil and Elam is presented and additionally compared with the experiment. Precursor diffusion and second-order reaction kinetics are combined to identify the influence of the porous substrate's microstructural parameters and the influence of precursor properties on the coating. The thickness of the deposited film is calculated for different depths inside the porous structure in relation to the precursor exposure time, the precursor vapor pressure, and other parameters. Good agreement with experimental results was obtained for ALD zirconiumdioxide (ZrO2) films using the precursors tetrakis(ethylmethylamido)zirconium and O2. The derivation can be adjusted to describe other features of ALD processes, e.g., precursor and reactive site losses, different growth modes, pore size reduction, and surface diffusion.

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“…In this section, we review characterization strategies that researchers have pursued to understand the morphology of thin-film perovskites and how they linked their findings to the obtained properties (Table 5). 15,46,[64][65][66]70,72,[76][77][78][79][80][81]83,[85][86][87]90,94,97,98,102,[104][105][106] To obtain compositional information, XPS is the most common technique. The information that can be obtained ranges from film contamination to the elemental composition within the topmost 1-10 nm of the film and its uniformity, chemical and electronic states, binding information, and depth information.…”

Section: Characterization Of Ultrathin Perovskite Filmsmentioning

confidence: 99%

Process–property relationship in high-k ALD SrTiO₃ and BaTiO₃: a review

et al. 2017

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bfPerovskites exhibit a wide range of remarkable material properties that have the potential to advance various scientific fields. These properties originate in their unique structure and composition. To leverage these properties in the ultrathin film regime, atomic-level control of thickness, composition, and crystal structure will be essential for creating next-generation perovskite devices. Atomic layer deposition (ALD) has the potential to enable these design prospects. However, its future use in the field will be dependent on the quality of the link between ALD process parameters and the perovskite phase.In this overview, we present work on barium and strontium titanate (BTO and STO) ultrathin films for high-k applications. We present ALD process strategies developed and optimized to achieve both desired composition and phase, yielding high dielectric constants and low leakage currents at the same time. We discuss thermal annealing, plasma treatment, and the use of seed layers and specialized precursors to improve the properties of BTO and STO by different enhancement mechanisms. In the ultrathin film regime, the understanding of macroscopic material properties will be dependent on the knowledge of the atomic scale arrangement. In conjunction with advances in manufacturing, we therefore also discuss novel strategies and techniques for characterization that will likely be significant in establishing a valid and reliable ALD process parameter-thin film dielectric property relationship.

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Atomic Layer Deposition of High‐k Oxides of the Group 4 Metals for Memory Applications

Cited by 132 publications

References 84 publications

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

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

Modeling precursor diffusion and reaction of atomic layer deposition in porous structures

Process–property relationship in high-k ALD SrTiO₃ and BaTiO₃: a review

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Atomic Layer Deposition of High‐k Oxides of the Group 4 Metals for Memory Applications

Cited by 132 publications

References 84 publications

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

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

Modeling precursor diffusion and reaction of atomic layer deposition in porous structures

Process–property relationship in high-k ALD SrTiO3 and BaTiO3: a review

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Process–property relationship in high-k ALD SrTiO₃ and BaTiO₃: a review