Low-voltage pentacene organic field-effect transistors with high-κ HfO2 gate dielectrics and high stability under bias stress
TL;DR: In this article, a low-voltage pentacene organic field effect transistors are demonstrated with high-κ hafnium dioxide gate dielectrics grown by atomic layer deposition at 200 °C.
Abstract: Low-voltage pentacene organic field-effect transistors are demonstrated (operating voltage of −3 V) with high-κ hafnium dioxide gate dielectrics grown by atomic layer deposition at 200 °C. A high hole mobility of 0.39 cm2/V s with low threshold voltage (<−0.5 V) and low subthreshold slope of 120 mV/dec is achieved with a HfO2 dielectric layer modified with a phosphonic acid based treatment. A high value of 94.8 nF/V s is obtained for the product of mobility and capacitance density. The devices show excellent bias stress stability with or without the phosphonic acid at the HfO2 gate dielectric surface.
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TL;DR: In this paper, a dry method for monolayer deposition of n-octylphosphonic acid (C8PA) on the surface of aluminium oxide (AlOx) is presented.
14 citations
TL;DR: In this article, ultra-thin (17 nm) HfO2 films on Si substrate are fabricated by RF sputtering and the films are annealed in nitrogen environment.
Abstract: Low leakage current density and high relative permittivity (dielectric constant) are the key factor in order to replace the SiO2 from Si-based technology toward its further downscaling. HfO2 thin films received significant attention due to its excellent optoelectronic properties. In this work, ultra-thin (17 nm) HfO2 films on Si substrate are fabricated by RF sputtering. As deposited films are amorphous in nature and in order to get the reasonable high dielectric constant, the films are annealed (700 degrees C, 30 min) in nitrogen environment. A high refractive index (2.08) and small grain size (similar to 10) nm were extracted from ellipsometry and XRD, respectively. The AFM study revealed a small RMS surface roughness 9 angstrom. For electrical characterization, films are integrated in metal-insulator-semiconductor capacitors structure. The oxide capacitance (C-ox), flat band capacitance (C-FB), flat band voltage (V-FB), and oxide-trapped charges (Q(ot)) calculated from high-frequency (1 MHz) C-V curve are 490, 241 pF, 1.21 V and 1.8 x 10(12) cm(-2), respectively. The dielectric constant calculated from accumulation capacitance is 17. The films show a low leakage current density 6.8 x 10(-9) A/cm(2) at +1 V, and this is due to the reduction in oxygen vacancies concentration as we performed annealing in N-2 environment. The band gap of the films is estimated from O 1s loss spectra and found 5.7 eV. The electron affinity (chi) and HfO2/Si barrier height (conduction band offset) extracted from UPS spectra are 1.88 and 2.17 eV, respectively. A trap state with 0.99 eV activation energy below the conduction band edge is found and assigned to the fourfold coordinated oxygen vacancy in m-HfO
13 citations
TL;DR: In this article, the authors demonstrate the feasibility of fabrication method combining classic and stencil lithography for producing simple organic rectifying circuits for use in radio frequency range, which are made of one organic Schottky diode followed by a MIM (Metal-Insulator-Metal) capacitor, integrated on the same flexible substrate.
11 citations
TL;DR: In this article, high performance chemical bath deposited CdS thin-film transistors (TFTs) using atomic layer deposited ZrO2 based high-k gate dielectric material.
Abstract: We demonstrate high performance chemical bath deposited CdS thin-film transistors (TFTs) using atomic layer deposited ZrO2 based high-k gate dielectric material. Our unique way of isolation of the CdS-based TFTs devices yielded significantly low leakage current as well as remarkable lower operating voltages (<5 V) which is four times smaller than the devices reported on CdS-based TFTs using SiO2 gate dielectric. Upon thermal annealing, the devices demonstrate even higher performance, including μFE exceeding 4 ± 0.2 cm2 V−1S−1, threshold voltage VT of 3.8 V, and Ion-off of 104–105, which hold much promise for applications in future electronic and optical devices.
11 citations
TL;DR: In this article, a simple 200°C hotplate-annealed zirconium titanium oxide (ZrTiO x ) films with excellent dielectric properties for low-voltage organic thin film transistors (OTFTs) were achieved.
11 citations
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TL;DR: Flexible active-matrix monochrome electrophoretic displays based on solution-processed organic transistors on 25-μm-thick polyimide substrates based on 1,888 transistors are demonstrated, which are the largest organic integrated circuits reported to date.
Abstract: At present, flexible displays are an important focus of research1,2,3 Further development of large, flexible displays requires a cost-effective manufacturing process for the active-matrix backplane, which contains one transistor per pixel One way to further reduce costs is to integrate (part of) the display drive circuitry, such as row shift registers, directly on the display substrate Here, we demonstrate flexible active-matrix monochrome electrophoretic displays based on solution-processed organic transistors on 25-μm-thick polyimide substrates The displays can be bent to a radius of 1 cm without significant loss in performance Using the same process flow we prepared row shift registers With 1,888 transistors, these are the largest organic integrated circuits reported to date More importantly, the operating frequency of 5 kHz is sufficiently high to allow integration with the display operating at video speed This work therefore represents a major step towards 'system-on-plastic'
1,577 citations
TL;DR: In this article, the properties of low-temperature Al2O3 ALD films were investigated versus growth temperature by depositing films on Si(100) substrates and quartz crystal microbalance (QCM) sensors.
Abstract: Al2O3 films were deposited by atomic layer deposition (ALD) at temperatures as low as 33 °C in a viscous-flow reactor using alternating exposures of Al(CH3)3 (trimethylaluminum [TMA]) and H2O. Low-temperature Al2O3 ALD films have the potential to coat thermally fragile substrates such as organic, polymeric, or biological materials. The properties of low-temperature Al2O3 ALD films were investigated versus growth temperature by depositing films on Si(100) substrates and quartz crystal microbalance (QCM) sensors. Al2O3 film thicknesses, growth rates, densities, and optical properties were determined using surface profilometry, atomic force microscopy (AFM), QCM, and spectroscopic ellipsometry. Al2O3 film densities were lower at lower deposition temperatures. Al2O3 ALD film densities were 3.0 g/cm3 at 177 °C and 2.5 g/cm3 at 33 °C. AFM images showed that Al2O3 ALD films grown at low temperatures were very smooth with a root-mean-squared (RMS) roughness of only 4 ± 1 A. Current−voltage and capacitance−voltage...
1,274 citations
Book•
01 Jan 1996
TL;DR: Semiconductor Models -- A General Introduction, Field Effect Introduction -- the J-FET and MESFET, and Electrostatics -- Mostly Qualitative Formulation.
Abstract: I. SEMICONDUCTOR FUNDAMENTALS. 1. Semiconductors -- A General Introduction. General Material Properties. Crystal Structure. Crystal Growth. 2. Carrier Modeling. The Quantization Concept. Semiconductor Models. Carrier Properties. State and Carrier Distributions. Equilibrium Carrier Concentrations. 3. Carrier Action. Drift. Diffusion. Recombination -- Generation. Equations of State. Supplemental Concepts. 4. Basics of Device Fabrication. Fabrication Processes. Device Fabrication Examples. R1. Part I Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part I Review Problem Sets and Answers. IIA. PN JUNCTION DIODES. 5. PN Junction Electrostatics. Preliminaries. Quantitative Electrostatic Relationships. 6. PN Junction Diode -- I-V Characteristics. The Ideal Diode Equation. Deviations from the Ideal. Special Considerations. 7. PN Junction Diode -- Small-Signal Admittance. Introduction. Reverse-Bias Junction Capacitance. Forward-Bias Diffusion Admittance. 8. PN Junction Diode -- Transient Response. Turn-Off Transient. Turn-On Transient. 9. Optoelectronic Diodes. Introduction. Photodiodes. Solar Cells. LEDs. IIB. BJTS AND OTHER JUNCTION DEVICES. 10. BJT Fundamentals. Terminology. Fabrication. Electrostatics. Introductory Operational Considerations. Performance Parameters. 11. BJT Static Characteristics. Ideal Transistor Analysis. Deviations from the Ideal. Modern BJT Structures. 12. BJT Dynamic Response Modeling. Equivalent Circuits. Transient (Switching) Response. 13. PNPN Devices. Silicon Controlled Rectifier (SCR). SCR Operational Theory. Practical Turn-on/Turn-off Considerations. Other PNPN Devices. 14. MS Contacts and Schottky Diodes. Ideal MS Contacts. Schottky Diode. Practical Contact Considerations. R2. Part II Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part II Review Problem Sets and Answers. III. FIELD EFFECT DEVICES. 15. Field Effect Introduction -- the J-FET and MESFET. General Introduction. J-FET. MESFET. 16. MOS Fundamentals. Ideal Structure Definition. Electrostatics -- Mostly Qualitative. Electrostatics -- Quantitative Formulation. Capacitance-Voltage Characteristics. 17. MOSFETs -- The Essentials. Qualitative Theory of Operation. Quantitative ID - VD Relationships. ac Response. 18. Nonideal MOS. Metal-Semiconductor Workfunction Difference. Oxide Charges. MOSFET Threshold Considerations. 19. Modern FET Structures. Small Dimension Effects. Select Structure Survey. R3. Part III Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part III Review Problem Sets and Answers. Appendix A. Elements of Quantum Mechanics. Appendix B. MOS Semiconductor Electrostatics -- Exact Solution. Appendix C. MOS C-V Supplement. Appendix D. MOS I-Vsupplement. Appendix E. List of Symbols. Appendix M. MATLAB Program Script.
1,048 citations
TL;DR: In this article, a pentacene organic thin-film transistor (OTFT) driven active matrix organic light-emitting diode (OLED) displays on flexible polyethylene terephthalete substrates were fabricated.
Abstract: We have fabricated pentacene organic thin-film transistor (OTFT) driven active matrix organic light-emitting diode (OLED) displays on flexible polyethylene terephthalete substrates These displays have 48×48 bottom-emission OLED pixels with two pentacene OTFTs used per pixel Parylene is used to isolate the OTFTs and OLEDs with good OTFT yield and uniformity
577 citations
05 Jul 2005
TL;DR: Progress is reported on in developing materials, processes, and devices for the realization of ultralow-cost printed RFID tags using novel pentacene and oligothiophene precursors for pMOS and ZnO nanoparticles for nMOS.
Abstract: Printed electronics provides a promising potential pathway toward the realization of ultralow-cost RFID tags for item-level tracking of consumer goods. Here, we report on our progress in developing materials, processes, and devices for the realization of ultralow-cost printed RFID tags. Using printed nanoparticle patterns that are subsequently sintered at plastic-compatible temperatures, low-resistance interconnects and passive components have been realized. Simultaneously, printed transistors with mobilities >10/sup -1/ cm/sup 2//V-s have been realized using novel pentacene and oligothiophene precursors for pMOS and ZnO nanoparticles for nMOS. AC performance of these devices is adequate for 135-kHz RFID, though significant work remains to be done to achieve 13.56-MHz operation.
501 citations