Mechanical and electrical properties of plasma and thermal atomic layer deposited Al2O3 films on GaAs and Si

Sah, R. E.; Driad, R.; Bernhardt, Frank; Kirste, Lutz; Leancu, Crenguta-Columbina; Czap, Heiko; Benkhelifa, F.; Mikulla, M.; Ambacher, O.

doi:10.1116/1.4804175

Cited by 16 publications

(10 citation statements)

References 39 publications

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“…The values of r s and r i were around 1 nm irrespective to t and OFR. Figure 3 also shows d m with an accuracy of ± 0.1 g/cm 3 [21] as a function of t , which was evaluated from the XRR measurements. The a -ITO films with t of more than 10 nm exhibited d m of about 7.2 g/cm 3 , which was almost the same as that of bulk ITO [12].…”

Section: Resultsmentioning

confidence: 99%

New Insights on Factors Limiting the Carrier Transport in Very Thin Amorphous Sn-Doped In2O3 Films with High Hall Mobility

2019

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We demonstrated that a mass density and size effect are dominant factors to limit the transport properties of very thin amorphous Sn-doped In 2 O 3 ( a -ITO) films. a -ITO films with various thicknesses ( t ) ranging from 5 to 50 nm were deposited on non-alkali glass substrates without intentional heating of the substrates by reactive plasma deposition with direct-current arc discharge. a -ITO films with t of more than 10 nm showed a high Hall mobility ( μ H ) of more than 50 cm 2 /V s. For 5-nm-thick a -ITO films, we found that μ H was as high as more than 40 cm 2 /V s. X-ray reflectivity measurement results revealed that the mass density ( d m ) determined the carrier transport in a -ITO films. For a -ITO films with t of more than 10 nm, d m had a high value of 7.2 g/cm 3 , whereas a -ITO films with t of less than 10 nm had low d m ranging from 6.6 to 6.8 g/cm 3 . Quantitative new insight from a size effect on the carrier transport is given for a -ITO films with t of less than 10 nm. This study shows that the ratio of t to mean free path of carrier electrons governed μ H .

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Section: Resultsmentioning

confidence: 99%

New Insights on Factors Limiting the Carrier Transport in Very Thin Amorphous Sn-Doped In2O3 Films with High Hall Mobility

2019

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“…Mechanical studies on ALD films mostly concentrated on elastic modulus, hardness measurement, or residual stress and can be classified into work on single compound film materials, mainly oxides and nitrides, prepared on stiff substrates, like Si or glass [15,16,17,18,19,20,21,22,23,24,25,26] and Al 2 O 3 [27]. The mechanical properties of nanolaminates films have also been investigated on stiff substrates [19,28,29,30,31,32,33,34].…”

Section: Introductionmentioning

confidence: 99%

Fracture Mechanics and Oxygen Gas Barrier Properties of Al2O3/ZnO Nanolaminates on PET Deposited by Atomic Layer Deposition

et al. 2019

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Rapid progress in the performance of organic devices has increased the demand for advances in the technology of thin-film permeation barriers and understanding the failure mechanisms of these material systems. Herein, we report the extensive study of mechanical and gas barrier properties of Al2O3/ZnO nanolaminate films prepared on organic substrates by atomic layer deposition (ALD). Nanolaminates of Al2O3/ZnO and single compound films of around 250 nm thickness were deposited on polyethylene terephthalate (PET) foils by ALD at 90 °C using trimethylaluminium (TMA) and diethylzinc (DEZ) as precursors and H2O as the co-reactant. STEM analysis of the nanolaminate structure revealed that steady-state film growth on PET is achieved after about 60 ALD cycles. Uniaxial tensile strain experiments revealed superior fracture and adhesive properties of single ZnO films versus the single Al2O3 film, as well as versus their nanolaminates. The superior mechanical performance of ZnO was linked to the absence of a roughly 500 to 900 nm thick sub-surface growth observed for single Al2O3 films as well as for the nanolaminates starting with an Al2O3 initial layer on PET. In contrast, the gas permeability of the nanolaminate coatings on PET was measured to be 9.4 × 10−3 O2 cm3 m−2 day−1. This is an order of magnitude less than their constituting single oxides, which opens prospects for their applications as gas barrier layers for organic electronics and food and drug packaging industries. Direct interdependency between the gas barrier and the mechanical properties was not established enabling independent tailoring of these properties for mechanically rigid and impermeable thin film coatings.

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“…The growth of films with ALD typically includes four steps: exposure of the surface to the first precursor, purge of the reaction chamber to remove the non-reacted precursors and the gaseous reaction by-products, exposure to the second precursor, and again purge or evacuation of the reactor chamber. The surface reactions can be accomplished using thermal chemistry or with the assistance of plasma [8]. The process temperature depends on the precursor and is typically in the range of 30 to 150 °C [9].…”

Section: Introductionmentioning

confidence: 99%

Label-free sensitivity of long-period gratings enhanced by atomic layer deposited TiO_2 nano-overlays

et al. 2015

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In this paper, we discuss an impact of thin titanium dioxide (TiO(2)) coatings on refractive index (RI) sensitivity and biofunctionalization of long-period gratings (LPGs). The TiO(2) overlays on the LPG surfaces have been obtained using atomic layer deposition (ALD) method. This method allows for a deposition of conformal, thickness-controlled, with well-defined optical properties, and high-RI thin films which are highly desired for optical fiber sensors. It has been found that for LPGs working at a dispersion turning point of higher order cladding modes only tens of nanometers of TiO(2) overlay thickness allow to obtain cladding mode transition effect, and thus significant improvement of RI sensitivity. When the TiO(2) overlay thickness reaches 70 nm, it is possible to obtain RI sensitivity exceeding 6200 nm/RIU in RI range where label-free sensors operate. Moreover, LPGs with TiO(2)-enhanced RI sensitivity have shown improved sensitivity to bacteria endotoxin (E. coli B lipopolysaccharide) detection, when TiO(2) surface is functionalized with endotoxin binding protein (adhesin) of T4 bacteriophage.

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Mechanical and electrical properties of plasma and thermal atomic layer deposited Al2O3 films on GaAs and Si

Cited by 16 publications

References 39 publications

New Insights on Factors Limiting the Carrier Transport in Very Thin Amorphous Sn-Doped In2O3 Films with High Hall Mobility

New Insights on Factors Limiting the Carrier Transport in Very Thin Amorphous Sn-Doped In2O3 Films with High Hall Mobility

Fracture Mechanics and Oxygen Gas Barrier Properties of Al2O3/ZnO Nanolaminates on PET Deposited by Atomic Layer Deposition

Label-free sensitivity of long-period gratings enhanced by atomic layer deposited TiO_2 nano-overlays

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