Effects of Electrical Bias Stress on the Performance of ZnO-Based TFTs Fabricated by RF Magnetron Sputtering

Navamathavan, R.; Yang, Eunho; Lim, Jae‐Hong; Hwang, Dae‐Kue; Oh, Jungkeun; Yang, J.; Jang, Jae‐Hyung; Park, Seong-Ju

doi:10.1149/1.2178651

Cited by 64 publications

(33 citation statements)

References 22 publications

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“…Silicon nitride is a promising material to be used as an insulator matrix in metal/ceramic granular systems and multilayers, and it has been proposed for applications in electronic devices due to its transport and optical properties and chemical inertness at high temperatures. [24][25][26][27] However, to our knowledge, not much has been reported about Fe/ Si 3 N 4 systems to obtain multilayered and granular magnetic materials. Structural characterization, prior to the analysis of the magnetic properties, has been achieved by using x-ray and transmission electron microscopy ͑TEM͒ techniques.…”

Section: Introductionmentioning

confidence: 99%

Effects of interparticle interactions in magneticFe/Si3N4granular systems

et al. 2010

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An experimental evidence of the progressive modification in the magnetic behavior of granular Fe/ Si 3 N 4 samples due to interaction effects between particles is reported. Microstructural features and local structure were determined by x-ray absorption spectroscopy and transmission electron microscopy to select granular samples with predetermined cluster size. Fe/ Si 3 N 4 systems have been characterized by ac-and dcmagnetization measurements to study the gradual evolution of magnetic properties of granular systems, where three different behaviors have been observed. As-deposited samples with Fe thickness layers of 2.5 nm, present a modified superparamagnetic behavior, due to very weak interactions between very small Fe clusters separated by a nonmagnetic FeN phase. An evolution of the average blocking temperature at intermediate fields ͑T B ϳ H 3/2 ͒ is observed, similar to noninteracting systems, but first signatures of a frozen spin state at low temperatures appear. Annealed samples exhibit a noticeable modification from the multilayer character to a random three-dimensional organization of Fe clusters embedded in a Si 3 N 4 matrix. After annealing, samples with initial Fe layer thickness of 0.7 nm provide iron cluster in the range of 1.3 nm and exhibit a superspinglass state, with a de Almeida-Thouless evolution of the energy barriers ͑T B ϳ H 2/3 ͒ that is explained in terms of increasing interparticle interactions. Moreover, annealed samples, with initial layer thickness of 1.3 nm, supply iron cluster of near 3 nm that present stronger interactions and yield a superferromagnetic state, likely provided by residual ultrasmall particles between the blocked clusters.

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Section: Introductionmentioning

confidence: 99%

Effects of interparticle interactions in magneticFe/Si3N4granular systems

et al. 2010

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“…[20][21][22] Several studies on bias-induced instabilities in ZnO-based TFTs have reported the deterioration of the current-voltage characteristics. [23][24][25] This effect could be manifested as a change in the field-effect mobility, a change in the subthreshold slope, or a shift in the V th voltage. Although the topic of ZnO-based TFTs has aroused growing interest over the past few years, effective approaches to solve this problem, including the development of new compensation circuits for AMOLED displays, [26,27] have not been forthcoming in the literature.…”

mentioning

confidence: 99%

Novel ZrInZnO Thin‐film Transistor with Excellent Stability

et al. 2009

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Nowadays, active-matrix organic light-emitting diode (AMOLED) technology has been intensively utilized in commercial large-size flat panel markets such as notebooks, personal computers, display monitors, and high-definition televisions. [1,2] This widespread use is due to the many attractive features that are offered by AMOLEDs, including wide viewing angles, high contrast ratios, low power consumption, and fast response times. Despite these advantages, one of the most critical issues for the technology is the inability to incorporate thin-film transistors (TFTs) in these large-sized applications (!7th generation glass size of 1.9 m Â 2.2 m (max)). The only mature technology compatible with producing large-sized panels (!7th generation) is based on amorphous Si (a-Si) TFTs, whose inferior long-term stability [3][4][5][6] under gate or/and drain bias stressed conditions hinders their utilization in AMOLED panels.Recently, ZnO-based TFTs have become attractive for use as driving devices in large-sized AMOLED applications, due to their better device performance and reliability; in addition, they offer large-size scalability features with good uniformity, and low product cost, comparable to their a-Si TFT counterparts. [7,8] Furthermore, the transparency of ZnO-based oxide semiconductor and their low-temperature process capability could open the opportunity to the next generation of applications, including ''see-through'' and/or ''flexible'' AMOLED displays, which cannot be realized via silicon-based TFT technologies due to their intrinsic limitations.There have been many reports of high-performance TFTs with oxide semiconductors, including ZnO, [8][9][10] InZnO, [11][12][13] ZnSnO, [14] and InGaZnO [15][16][17][18][19] as the channel materials. The field-effect mobilities (m FE ), sub-threshold gate swing (S), and I on/ off ratios of ZnO-based TFTs have been dramatically improved since Hosono and coworkers reported the usage of amorphous InGaZnO as a channel material using physical-vapor-deposition techniques.[7] Thus, the device performance of ZnO-based TFTs reported in the literature includes high mobility (>10 cm 2 V s À1 ), excellent sub-threshold gate-voltage swing (<0.4 V decade À1 ), and high I on/off ratios (>10 7 ), which are superior to those found in a-Si TFT applications. [7,8,15,16,18,19] However, the stability of ZnO-based TFT devices has remained the most important and critical issue still to be resolved to allow them to be used as driving devices in AMOLED displays. This is because any positive shift in the threshold voltage (V th ) of the driving transistor during the on-state bias stressed condition causes a rapid drop in the output drain current, leading to reduction in the luminance of the OLED device. The nonuniformity in the V th shift of the pixel driving transistors as a result of the different data voltages obviously causes the well-known problem of the image sticking in the resulting panel brightness. [20][21][22] Several studies on bias-induced instabilities in ZnO-based TFTs have reported...

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“…Although the on/off ratio and S.S. of our top-gate transparent ZnO TFT appeared to be not very good, its device stability was outstanding, mainly because this top-gate structure does not allow sputtering-induced damage on the dielectric surface unlike the bottom-gate TFT. [14,[29][30][31] Figure 4e and f displays the drain current-voltage (I D -V D ) output curves obtained from the p-channel (pentacene) and n-channel (ZnO) TFTs, respectively, as prepared on nanohybrid dielectric layers. The www.afm-journal.de saturation currents of 0.28 and 0.80 mA were achieved from pentacene-and ZnO-based devices, respectively, under a V G of À3 V for the former and 3 V for the latter.…”

Section: Channelmentioning

confidence: 99%

Transparent Photo‐Stable Complementary Inverter with an Organic/Inorganic Nanohybrid Dielectric Layer

Lee

et al. 2009

Adv Funct Materials

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Transparent electronics has been one of the key terminologies forecasting the ubiquitous technology era. Several researchers have thus extensively developed transparent oxide‐based thin‐film transistors (TFTs) on glass and plastic substrates. However, work in transparent electronics has been limited mostly to high‐voltage devices operating at more than a few tens of volts, and has mainly focused on transparent display drivers. Low‐voltage logic devices, such as transparent complementary inverters, operating in an electrically stable and photo‐stable manner, are now very necessary to practically realize transparent electronics. Electrically stable dielectrics with high strength and high capacitance must also be proposed to support this mission, and simultaneously these dielectrics must be compatible with both n‐ and p‐channel TFTs in device fabrication. Here, a nanohybrid dielectric layer that is composed of multiple units of inorganic oxide and organic self‐assembled monolayer is proposel to support a transparent complementary TFT inverter operating at 3 V.

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Effects of Electrical Bias Stress on the Performance of ZnO-Based TFTs Fabricated by RF Magnetron Sputtering

Cited by 64 publications

References 22 publications

Effects of interparticle interactions in magneticFe/Si3N4granular systems

Effects of interparticle interactions in magneticFe/Si3N4granular systems

Novel ZrInZnO Thin‐film Transistor with Excellent Stability

Transparent Photo‐Stable Complementary Inverter with an Organic/Inorganic Nanohybrid Dielectric Layer

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