Correlation of nanochemistry and electrical properties in HfO2 films grown by metalorganic molecular-beam epitaxy

Moon, Tae Hyoung; Ham, Moon Ho; Myoung, Jae Min

doi:10.1063/1.1873049

Cited by 18 publications

(10 citation statements)

References 15 publications

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“…However, the performance of these devices is severely constrainted due to the low dielectric constant of SiO 2 gate dielectric layers. In contrast, HfO 2 has steadily emerged as an important candidate to work as a gate insulator due to its high dielectric constant and relatively low leakage current [6][7][8][9][10][11][12][13][14]. As a result, integrating ZnO nanowire FETs with HfO 2 gate insulators is expected to deliver substantially enhanced device performance such as transconductance (g m ), current on/off ratio (I on /I off ), and carrier mobility (µ e ).…”

Section: Introductionmentioning

confidence: 99%

Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Moon

Jeong

et al. 2006

Nanotechnology

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The effects of different annealing atmospheres on the chemical surface structure of HfO2 gate dielectric layers have been evaluated in terms of the improvement in the transconductance (gm), current on/off ratio (Ion/Ioff), and carrier mobility (μe) of a back-gated ZnO nanowire field-effect transistor (FET). Compared to O2 and N2 annealed HfO2-gated transistors, the H2 annealed HfO2-gated ZnO nanowire FET exhibited a higher transconductance of 1.77 × 10−7 A V−1, on/off current ratio of ∼1.2 × 104, and electron mobility of 11.90 cm2 V−1 s−1.

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Section: Introductionmentioning

confidence: 99%

Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Moon

Jeong

et al. 2006

Nanotechnology

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“…The enhanced accumulation capacitance is due to the increased concentration of silicate with its high dielectric constant. [16] Oxygen vacancies are the principal source of oxide charges and bulk defects in Ta 2 O 5 , and they can be efficiently reduced in an oxidizing ambience at the beginning or during the deposition step and by post-annealing treatments. Figure 4 shows the C-V characteristics of the samples deposited in working gas with different O 2 /Ar ratios and subsequently annealed at 700 • C in pure Ar ambience.…”

Section: C-v C-v C-v and Dielectric Characteristicsmentioning

confidence: 99%

Effects of O₂/Ar ratio and annealing temperature on electrical properties of Ta₂O₅film prepared by magnetron sputtering

Huang¹,

Pei-Hong²,

Chen³

2013

Chinese Phys. B

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The effects of the oxygen-argon ratio on electric properties of Ta 2 O 5 film prepared by radio-frequency magnetron sputtering were investigated. The Ta 2 O 5 partially transforms from the amorphous phase into the crystal phase when annealing temperatures are 800 • C or higher. The lattice constant of Ta 2 O 5 decreases with the increase of the O 2 /Ar ratio, which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process. For the films deposited in working gas mixtures with different O 2 /Ar ratios and subsequently annealed at 700 • C, the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O 2 /Ar ratio from 0 to 1. Considering the presence of an SiO 2 layer between the film and the silicon substrate, the optimal dielectric constant of Ta 2 O 5 film was estimated to be 31. Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies, and the oxygen vacancy density and leakage current of Ta 2 O 5 film both decrease with the increase of the O 2 /Ar ratio. The leakage current decreases after annealing treatment and it is minimized at 700 • C. However, when the annealing temperature is 800 • C or higher, it increases slightly, which results from the partially crystallized Ta 2 O 5 layer containing defects such as grain boundaries and vacancies.

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“…On the other hand, optical applications require uniform, smooth, dense and stoichiometric films, since the extrinsic causes of optical losses include surface roughness, impurities, film composition and structural non-uniformity. The overall performance of an optical coating depends Various physical and chemical methods have been employed to grow HfO2 thin films, such as electron-beam evaporation [11], reactive ion plating [12], metal-organic molecular beam epitaxy [13], atomic layer deposition [14,15], etc. Each method has its own merits and demerits.…”

Section: Introductionmentioning

confidence: 99%

Study of the structure, roughness and optical properties of HfO₂ coatings deposited on microscopic glass substrates

Rabadzhiyska

Ormanova

Valkov

et al. 2022

J. Phys.: Conf. Ser.

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In this work, we deposited HfO2 films on microscopic glasses by direct current (DC) magnetron sputtering for different deposition times, namely 120 min and 180 min. The phase composition of the coatings was assessed by X-ray diffraction (XRD). The surface roughness, the optical constants, the refractive index n, the extinction coefficient k and the thickness of the prepared HfO2 coatings were estimated by ellipsometric measurements. The XRD results pointed to the presence of a polycrystalline monoclinic phase. A slight difference was found in the surface roughness of the two HfO2 films, which was 5.1 nm and 5.7 nm, respectively, for the deposition times of 120 minutes and 180 minutes. The optical constants n and k were determined at the wavelength of 630 nm by using the Cauchy model. The results showed almost the same value of the refractive index for both films (1.88 and 1.89), but a higher extinction coefficient (0.01) for the film grown for 180 minutes, compared to a value of 0.007 for the one deposited for 120 minutes. The films thickness was 410 nm and 780 nm for deposition times of 120 minutes and 180 minutes, respectively. The deposited HfO2 films were transparent, with the longer deposition time corresponding to an improved reflection (57%), compared to the 28% reflection for the film deposited for 120 minutes.

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Correlation of nanochemistry and electrical properties in HfO2 films grown by metalorganic molecular-beam epitaxy

Cited by 18 publications

References 15 publications

Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Effects of O₂/Ar ratio and annealing temperature on electrical properties of Ta₂O₅film prepared by magnetron sputtering

Study of the structure, roughness and optical properties of HfO₂ coatings deposited on microscopic glass substrates

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Correlation of nanochemistry and electrical properties in HfO2 films grown by metalorganic molecular-beam epitaxy

Cited by 18 publications

References 15 publications

Chemical surface passivation of HfO2films in a ZnO nanowire transistor

Chemical surface passivation of HfO2films in a ZnO nanowire transistor

Effects of O2/Ar ratio and annealing temperature on electrical properties of Ta2O5film prepared by magnetron sputtering

Study of the structure, roughness and optical properties of HfO2 coatings deposited on microscopic glass substrates

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Product

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Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Effects of O₂/Ar ratio and annealing temperature on electrical properties of Ta₂O₅film prepared by magnetron sputtering

Study of the structure, roughness and optical properties of HfO₂ coatings deposited on microscopic glass substrates