Enhancement of metal oxide deposition rate and quality using pulsed plasma-enhanced chemical vapor deposition at low frequency

Seman, Michael; Richards, David; Rowlette, Pieter C.; Kubala, Nicholas G.; Wolden, Colin A.

doi:10.1116/1.2966425

Cited by 16 publications

(12 citation statements)

References 33 publications

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“…Pulsed PECVD has been reported for many materials, with improvement in film quality for some. 12,13 In this work, we used pulsed PECVD to fabricate undoped ZnO films at low temperature (200°C) from diethylzinc (DEZ) and nitrous oxide (N 2 O) or carbon dioxide (CO 2 ). Pulsed-PECVDdeposited ZnO TFTs with low-leakage PEALD Al 2 O 3 as the gate dielectric have field-effect mobility of 15 cm 2 /V s.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Zhao

Mourey

Jackson

2009

Journal of Elec Materi

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We report high-quality ZnO thin films deposited at low temperature (200°C) by pulsed plasma-enhanced chemical vapor deposition (pulsed PECVD). Process byproducts are purged by weak oxidants N 2 O or CO 2 to minimize parasitic CVD deposition, resulting in high-refractive-index thin films. Pulsed-PECVD-deposited ZnO thin-film transistors were fabricated on plasmaenhanced atomic layer deposition (PEALD) Al 2 O 3 dielectric and have a fieldeffect mobility of 15 cm 2 /V s, subthreshold slope of 370 mV/dec, threshold voltage of 6.6 V, and current on/off ratio of 10 8 . Thin-film transistors (TFTs) on thermal SiO 2 dielectric have a field-effect mobility of 7.5 cm 2 /V s and threshold voltage of 14 V. For these devices, performance may be limited by the interface between the ZnO and the dielectric.

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Section: Introductionmentioning

confidence: 99%

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Zhao

Mourey

Jackson

2009

Journal of Elec Materi

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“…24,25,27 Premixed process gases were delivered through a showerhead that also served as the powered electrode. Substrates were clamped to the grounded electrode, and the system was operated as a hot wall reactor (25-180°C).…”

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confidence: 99%

“…This is a departure from our previous studies, in which both O 2 and the precursor were delivered continuously. [20][21][22][23][24][25][26] Due to its high vapor pressure (235 Torr at 25 °C), it was not possible with existing equipment to control the deposition rate with angstrom resolution using continuous delivery of SiCl 4 . Instead, both the precursor and plasma were pulsed, while O 2 flowed continuously.…”

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confidence: 99%

“…The amount of this latter contribution can be adjusted by varying the precursor density in the chamber at plasma ignition. The process has been demonstrated to deliver digital control over film thickness and produce a high degree of conformality at significant rates (>20 nm/min). , …”

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confidence: 99%

“…SiO 2 thin films were deposited in a capacitively coupled PECVD system that was previously used for pulsed PECVD/PE-ALD of both Al 2 O 3 and ZnO. ,, Premixed process gases were delivered through a showerhead that also served as the powered electrode. Substrates were clamped to the grounded electrode, and the system was operated as a hot wall reactor (25−180 °C).…”

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confidence: 99%

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Digital Control of SiO₂ Film Deposition at Room Temperature

2009

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In this Letter, we propose and demonstrate a robust process for digital control of high quality SiO 2 thin films at room temperature using pulsed plasma-enhanced chemical vapor deposition (PECVD). Plasma activation of the SiCl 4 precursor is critical, as atomic layer deposition does not occur under these conditions. Subangstrom control over deposition rate was obtained by adjusting the density of SiCl 4 present at plasma ignition. The intrinsic refractive index of 1.46 was obtained at rates between 0.8 and 1.6 Å/pulse. No impurities were detected by either X-ray photoelectron spectroscopy (XPS) or Fourier transform infrared (FTIR) in films deposited under optimal conditions. Atomic layer deposition (ALD) is a leading technique for thin film deposition. Growth proceeds through cycles of sequential, self-limiting surface reactions that impart nanoscale control over thickness and composition. Since its inception over three decades ago, 1 ALD has been refined and successfully demonstrated for numerous materials, particularly metal oxides. 2 However, a number of materials have proven difficult to deposit by ALD. Perhaps the most auspicious example is silicon dioxide, given its role as the most important and widely used dielectric in the integrated circuit industry. 3 The outstanding chemical, optical, and electrical properties of vapor-deposited SiO 2 make it an important component for photovoltaics, 4,5 optics, 6 and barrier applications. 7,8 Continued miniaturization of device structures and the extension to flexible substrates requires deposition techniques that impart nanoscale control over thickness at low temperature. Despite the critical importance of SiO 2 and maturation of ALD technology, a robust, low temperature process for digital control of SiO 2 growth remains elusive.A primary challenge to SiO 2 ALD is overcoming the limited reactivity of silicon-containing precursors. The George group first demonstrated silica ALD using SiCl 4 and H 2 O as coreagents, with the two separate half-reactions combining to produce the overall reaction SiCl 4 + 2H 2 O f SiO 2 + 4HCl. 9 However, this group also acknowledged the limitations of this process including high temperature requirements (600-800 K), large reactant exposure (∼10 9 L, 1 L ) 10 -6 Torr · s), and the production of corrosive HCl as a reaction product. 10 Low temperature (<200°C ) processing is critical for extending ALD to temperaturesensitive substrates and biological applications and to maintain device integrity. To this end, a number of groups have developed catalytic reaction strategies in order to reduce the temperature requirements. 10-12 Though high rates 12 and room temperature 10,11 synthesis have been demonstrated, these processes create added complexity and raise concerns about impurity incorporation. 13 Plasma-enhanced ALD (PE-ALD) has been demonstrated to reduce temperature requirements by employing plasma generated radicals (O) to complete the oxidation step. 14 Jiang and co-workers accomplished PE-ALD of silica at room temperature using TEOS ...

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Preparation of films from aluminum acetylacetonate by plasma sputtering

Nielsen

Silva

Cruz

et al. 2013

Surface & Interface Analysis

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Aluminum acetylacetonate has been reported as a precursor for the deposition of alumina films using different approaches. In this work, alumina-containing films were prepared by plasma sputtering this compound, spread directly on the powered lowermost electrode of a reactor, while grounding the substrates mounted on the topmost electrode. Radiofrequency power (13.56 MHz) was used to excite the plasma from argon atmosphere at a working pressure of 11 Pa. The effect of the plasma excitation power on the properties of the resulting films was studied. Film thickness and hardness were measured by profilometry and nanoindentation, respectively. The molecular structure and chemical composition of the layers were analyzed by Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Surface micrographs, obtained by scanning electron microscopy, allowed the determination of the sample morphology. Grazing incidence X-ray diffraction was employed to determine the structure of the films. Amorphous organic layers were deposited with thicknesses of up to 7 mm and hardness of around 1.0 GPa. The films were composed by aluminum, carbon, oxygen and hydrogen, their proportions being strongly dependent on the power used to excite the plasma. A uniform surface was obtained for low-power depositions, but particulates and cracks appeared in the high-power prepared materials. The presence of different proportions of aluminum oxide in the coatings is ascribed to the different activations promoted in the metalorganic molecule once in the plasma phase.

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Enhancement of metal oxide deposition rate and quality using pulsed plasma-enhanced chemical vapor deposition at low frequency

Abstract: Effect of wall conditions on the self-limiting deposition of metal oxides by pulsed plasma-enhanced chemical vapor deposition

Cited by 16 publications

References 33 publications

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Digital Control of SiO₂ Film Deposition at Room Temperature

Preparation of films from aluminum acetylacetonate by plasma sputtering

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Enhancement of metal oxide deposition rate and quality using pulsed plasma-enhanced chemical vapor deposition at low frequency

Abstract: Effect of wall conditions on the self-limiting deposition of metal oxides by pulsed plasma-enhanced chemical vapor deposition

Cited by 16 publications

References 33 publications

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Low-Temperature Pulsed-PECVD ZnO Thin-Film Transistors

Digital Control of SiO2 Film Deposition at Room Temperature

Preparation of films from aluminum acetylacetonate by plasma sputtering

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Digital Control of SiO₂ Film Deposition at Room Temperature