Al2O3/TiO2 nanolaminate gate dielectric films with enhanced electrical performances for organic field-effect transistors

Baek, Yonghwa; Lim, Sooman; Kim, Lae Ho; Park, Seonuk; Lee, Seung Woo; Oh, Tae Hwan; Kim, Se Hyun; Park, Jin Young

doi:10.1016/j.orgel.2015.10.025

Cited by 41 publications

(27 citation statements)

References 31 publications

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“…Figure 7d shows the dark J-V curve in semilogarithmic scale under positive and negative biases at room temperature. As can be seen, the leakage current density at −2 V is in the order of 10 −5~1 0 −4 A/cm 2 , which is in the same order of magnitude reported by Wei et al [5] and Baek et al [1] that used PEALD and tetrakis dimethylamino titanium (TDMAT) as precursor to growth TiO2 (20 nm) on Si.…”

Section: Current Density-voltage Measurementssupporting

confidence: 82%

“…Titanium dioxide (TiO 2 ) thin films and nanolaminates have a significant number of promising applications in different areas, such as microelectronics [1][2][3][4][5][6], photovoltaics [7,8], photocatalysis [9][10][11] fuel cells [12], sensors [13][14][15][16], anti-reflective coating applications [17], biomedical coatings [18,19] and food packaging applications [20]. The properties and applicability of TiO 2 thin films are intrinsically related to their crystal structure.…”

Section: Introductionmentioning

confidence: 99%

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MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

et al. 2020

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In this paper, we report the plasma-enhanced atomic layer deposition (PEALD) of TiO2 and TiO2/Al2O3 nanolaminate films on p-Si(100) to fabricate metal-oxide-semiconductor (MOS) capacitors. In the PEALD process, we used titanium tetraisopropoxide (TTIP) as a titanium precursor, trimethyl aluminum (TMA) as an aluminum precursor and O2 plasma as an oxidant, keeping the process temperature at 250 °C. The effects of PEALD process parameters, such as RF power, substrate exposure mode (direct or remote plasma exposure) and Al2O3 partial-monolayer insertion (generating a nanolaminate structure) on the physical and chemical properties of the TiO2 films were investigated by Rutherford backscattering spectroscopy (RBS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), and field emission scanning electron microscopy (FESEM) techniques. The MOS capacitor structures were fabricated by evaporation of Al gates through mechanical mask on PEALD TiO2 thin film, followed by evaporation of an Al layer on the back side of the Si substrate. The capacitors were characterized by current density-voltage (J-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Our results indicate that RF power and exposure mode promoted significant modifications on the characteristics of the PEALD TiO2 films, while the insertion of Al2O3 partial monolayers allows the synthesis of TiO2/Al2O3 nanolaminate with well-spaced crystalline TiO2 grains in an amorphous structure. The electrical characterization of the MOS structures evidenced a significant leakage current in the accumulation region in the PEALD TiO2 films, which could be reduced by the addition of partial-monolayers of Al2O3 in the bulk of TiO2 films or by reducing RF power.

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Section: Current Density-voltage Measurementssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

et al. 2020

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“…In an OFETs device, the charge density (Q = CV) localized at the first few semiconductor monolayers close to the interface is proportional to the dielectric constant [11,17]. Figure 2 illustrates a parallel-plate metal-insulator-metal (MIM) capacitor that is used to measure the dielectric properties of materials.…”

Section: Resultsmentioning

confidence: 99%

Low-Power Flexible Organic Field-Effect Transistors with Solution-Processable Polymer-Ceramic Nanoparticle Composite Dielectrics

et al. 2020

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Polymer-ceramic dielectric composites have been of great interest because they combine the processability of polymers with the desired dielectric properties of the ceramics. We fabricated a low voltage-operated flexible organic field-effect transistor (OFET) based on crosslinked poly (4-vinyl phenol) (PVP) polymer blended with novel ceramic calcium titanate nanoparticles (CaTiO3 NPs) as gate dielectric. To reduce interface roughness caused by nanoparticles, it was further coated with a very thin PVP film. The resulting OFET exhibited much lower operated voltage (reducing from –10.5 V to –2.9 V), a relatively steeper threshold slope (~0.8 V/dec) than those containing a pure PVP dielectric. This is ascribed to the high capacitance of the CaTiO3 NP-filled PVP insulator, and its smoother and hydrophobic dielectric surface proved by atomic force microscopy (AFM) and a water contact angle test. We also evaluated the transistor properties in a compressed state. The corresponding device had no significant degradation in performance when bending at various diameters. In particular, it operated well continuously for 120 hours during a constant bending stress. We believe that this technology will be instrumental in the development of future flexible and printed electronic applications.

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“…In the OTFT devices, the charge density (Q = CV) localized at the first few semiconductor monolayers close to the interface is proportional to the dielectric constant [14,15]. The electrical properties of dielectric were determined by measuring a parallel-plate metal-insulator-metal (MIM) capacitor, as plotted in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors

2020

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A high-quality dielectric layer is essential for organic thin-film transistors (OTFTs) operated at a low-power consumption level. In this study, a facile improved technique for the synthesis of solution-processed silica is proposed. By optimizing the synthesis and processing technique fewer pores were found on the surface of the film, particularly no large holes were observable after improving the annealing process, and the improved solution–gelation (sol–gel) SiOx dielectric achieved a higher breakdown strength (1.6 MV/cm) and lower leakage current density (10−8 A/cm2 at 1.5 MV/cm). Consequently, a pentacene based OTFT with a high field effect mobility (~1.8 cm2/Vs), a low threshold voltage (−1.7 V), a steeper subthreshold slope (~0.4 V/dec) and a relatively high on/off ratio (~105) was fabricated by applying a hybrid gate insulator which consisted of improved sol–gel SiOx and polyvinyl phenol (PVP). This could be ascribed to both the high k of SiOx and the smoother, hydrophobic dielectric surface with low trap density, which was proved by atomic force microscopy (AFM) and a water contact angle test, respectively. Additionally, we systematically studied and evaluated the stability of devices in the compressed state. The devices based on dielectric fabricated by conventional sol–gel processes were more susceptible to the curvature. While the improved device presented an excellent mechanic strength, it could still function at the higher bending compression without a significant degradation in performance. Thus, this solution-process technology provides an effective approach to fabricate high-quality dielectric and offers great potential for low-cost, fast and portable organic electronic applications.

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Al2O3/TiO2 nanolaminate gate dielectric films with enhanced electrical performances for organic field-effect transistors

Cited by 41 publications

References 31 publications

MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

Low-Power Flexible Organic Field-Effect Transistors with Solution-Processable Polymer-Ceramic Nanoparticle Composite Dielectrics

Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors

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