1,720,969 research outputs found
High-Performance Al-Sn-Zn-In-O Thin-Film Transistors: Impact of Passivation Layer on Device Stability
No full textWe fabricated high-performance thin-film transistors (TFTs) with an amorphous-Al-Sn-Zn-In-O (a-AT-ZIO) channel deposited by cosputtering using a dual Al-Zn-O and In-Sn-O target. The fabricated AT-ZIO TFTs, which feature a bottom-gate and bottom-contact configuration, exhibited a high field-effect mobility of 31.9 cm(2)/V . s, an excellent subthreshold gate swing of 0.07 V/decade, and a high I-on/(off) ratio of > 10(9), even below the process temperature of 250 degrees C. In addition, we demonstrated that the temperature and bias-induced stability of the bottom-gate TFT structure can significantly be improved by adopting a suitable passivation layer of atomic-layer-deposition- derived Al2O3 thin film
Impact of device configuration on the temperature instability of Al–Zn–Sn–O thin film transistors
No full textWe compared the effect of the temperature on the device stability of Al-Zn-Sn-O (AZTO) thin film transistors (TFTs) with top gate and bottom gate architectures. While the bottom gate device without any passivation layer on the AZTO channel layer showed a large threshold voltage (V-th) shift of 1.6 V after heating it from 298 to 398 K, the naturally passivated top gate device exhibited a smaller V-th shift of 0.6 V. This different behavior is discussed based on the concept of the thermal activation energy of the subthreshold drain current. It is proposed that the suitable passivation and lower interfacial trap density for the top gate TFT are responsible for its superior temperature stability compared to the bottom gate device. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3236694
Transparent Oxide Thin-Film Transistors Composed of Al and Sn-doped Zinc Indium Oxide
No full textWe have fabricated the transparent bottom gate thin-film transistors (TFTs) using Al and Sn-doped zinc indium oxide (AT-ZIO) as an active layer. The AT-ZIO active layer was deposited by RF magnetron sputtering at room temperature, and the AT-ZIO TFT showed a field effect mobility of 15.6 cm(2)/Vs even before annealing. The mobility increased with increasing the In2O3 content and postannealing temperature up to 250 degrees C. The AT-ZIO TFT exhibited a field effect mobility of 30.2 cm(2) /Vs, a subthreshold swing of 0.17 V/dec, and an on/off current ratio of more than 10(9)
Characterization of Nonvolatile Memory Behaviors of Al/Poly(vinylidene fluoride-trifluoroethylene)/Al2O3/ZnO Thin-Film Transistors
No full textThe combination of a ferroelectric polymer and an oxide semiconductor is a very promising solution to realize embeddable nonvolatile memory thin-film transistors (TFTs) for novel electronic devices. Memory TFTs with a gate structure of Al/80 nm-poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)]/4nm Al2O3/5nm ZnO were fabricated and their programming characteristics were investigated. Good performances in memory and transistor behaviors were successfully confirmed. When the voltage pulses of +/- 15 V and 990 ms were employed, a memory on/off ratio of 4400 was obtained. It was found that the initial memory on/off ratio was closely related to the applied programming conditions such as pulse amplitude and width of programming voltage signals. Retention behaviors were also sensitively affected by the programming conditions. The initial memory on/off ratio of approximately 300 decreased to 3.4 after a lapse of 10(4) s when the programming voltage, pulse duration, and gate bias during the retention period were set to be +/- 18 V, 500 ms, and open, respectively. (C) 2010 The Japan Society of Applied Physic
Improvement in the photon-induced bias stability of Al–Sn–Zn–In–O thin film transistors by adopting AlOx passivation layer
No full textThis study examined the impact of the passivation layer on the light-enhanced bias instability of Al-Sn-Zn-In-O (AT-ZIO) thin film transistors. The suitably passivated device exhibited only a threshold voltage (V-th) shift of 0.72 V under light-illuminated negative-thermal stress conditions, whereas the device without a passivation layer suffered from a huge negative V-th shift of >11.5 V under identical conditions. The photocreated hole trapping model could not itself explain this behavior. Instead, the light-enhanced V-th instability of the unpassivated device would result mainly from the photodesorption of adsorbed oxygen ions after exposing the AT-ZIO back-surface in an ambient atmosphere. (C) 2010 American Institute of Physics. [doi:10.1063/1.3432445
Nondestructive Readout Operation of Oxide-Thin-Film-Transistor-Based 2T-Type Nonvolatile Memory Cell
No full textA two-transistor-type nonvolatile memory cell composed of one-access and one-memory thin-film transistors (TFTs) was demonstrated. ZnO and poly(vinylidene fluoride-trifluoroethylene) were employed as semiconducting channels for both TFTs and ferroelectric-gate insulator for memory TFT, respectively, in which the cell structures and fabrication procedures were so carefully designed and optimized as to effectively incorporate both TFTs on the same glass substrate without any critical process damage even below 200 degrees C. The fabricated memory cell successfully showed the write and nondestructive readout operations
Effect of ZnO channel thickness on the device behaviour of nonvolatile memory thin film transistors with double-layered gate insulators of Al2O3 and ferroelectric polymer
No full textPoly(vinylidene fluoride trifluoroethylene) and ZnO were employed for nonvolatile memory thin film transistors as ferroelectric gate insulator and oxide semiconducting channel layers, respectively. It was proposed that the thickness of the ZnO layer be carefully controlled for realizing the lower programming voltage, because the serially connected capacitor by the formation of a fully depleted ZnO channel had a critical effect on the off programming voltage. The fabricated memory transistor with Al/P(VDF-TrFE) (80 nm)/Al2O3 (4 nm)/ZnO (5 nm) exhibits encouraging behaviour such as a memory window of 3.8V at the gate voltage of -10 to 12V, and 10(7) on/off ratio, and a gate leakage current of 10(-11) A
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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