Browsing by Author "Cheng, Chun-Cheng"

Now showing 1 - 6 of 6

Amorphous InGaZnO Thin-Film Transistors Compatible With Roll-to-Roll Fabrication at Room Temperature
(2012-01-01)
Yu, Ming-Jiue
;
Yeh, Yung-Hui
;
Cheng, Chun-Cheng
;
Lin, Chang-Yu
;
Ho, Geng-Tai
High-performance amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) are successfully fabricated on a colorless polyimide substrate using a top-gate self-aligned structure. All thin films are deposited by roll-to-roll-compatible sputtering processes at room temperature. The maximum field-effect mobility is 18 cm(2)/V . s, the threshold voltage is - 1.35 V, the subthreshold slope is 0.1 V/decade, and the on/off current ratio is about 10(5). The results highlight that excellent device performance can be realized in a-IGZO TFTs without compromising manufacturability.
Effects of Mechanical Strains on the Characteristics of Top-Gate Staggered a-IGZO Thin-Film Transistors Fabricated on Polyimide-Based Nanocomposite Substrates
(2012-07-01)
Lin, Chang-Yu
;
Chien, Chih-Wei
;
Wu, Chung-Chih
;
Yeh, Yung-Hui
;
Cheng, Chun-Cheng
In this paper, we had successfully implemented flexible top-gate staggered amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) on colorless and transparent polyimide (PI)-based nanocomposite substrates using fully lithographic and etching processes that are compatible with existing TFT mass fabrication technologies. The use of the selectively coated release layer between the nanocomposite PI film and the glass carrier ensured smooth debonding of the plastic substrate after TFT fabrication. The TFTs showed decent performances (with mobility > 10 cm(2)/V . s) either as fabricated or as debonded from the carrier glass. By bending the devices to different radii of curvature (from a flat state to an outward bending radius of 5 mm), influences of mechanical strains on the characteristics of flexible a-IGZO TFTs were also investigated. In general, the mobility of the flexible a-IGZO TFT increased with the tensile strain, whereas the threshold voltage decreased with the tensile strain. The variation of the mobility in a-IGZO TFTs versus the strain appeared smaller than those observed for amorphous silicon TFTs.
Fabrication of high-performance, low-temperature solution processed amorphous indium oxide thin-film transistors using a volatile nitrate precursor
(2015-01-01)
Choi, Chang-Ho
;
Han, Seung-Yeol
;
Su, Yu-Wei
;
Fang, Zhen
;
Lin, Liang-Yu
In this study, we fabricate amorphous indium oxide thin film transistors (TFTs) on a display glass substrate at various annealing temperatures from 200 degrees C to 300 degrees C. Using a volatile nitrate precursor, we were able to fabricate TFTs with excellent device performance within this annealing temperature range. Amorphous In2O3 films could be obtained by carefully controlling the film thickness and annealing temperature. TFTs based on amorphous In2O3 channel layers with an average mobility as high as 7.5 cm(2) V-1 s(-1), an I-on/I-off ratio of 10(7), and V-on = -5 V could be fabricated at 300 degrees C annealing temperature in air. The devices prepared at 200 degrees C still exhibit transistor characteristics with an average mobility of 0.04 cm(2) V-1 s(-1), an Ion/Ioff ratio of 10(5), and V-on = 0 V. The temperature effects on the device performances are elucidated based on X-ray photoelectron spectroscopy and thermal gravimetric analysis characterization results of precursors and the resulting amorphous In2O3 thin films.
Improvements in the reliability of a-InGaZnO thin-film transistors with triple stacked gate insulator in flexible electronics applications
(2015-11-30)
Chen, Hua-Mao
;
Chang, Ting-Chang
;
Tai, Ya-Hsiang
;
Chen, Kuan-Fu
;
Chiang, Hsiao-Cheng
This study examined the impact of the low-temperature stacking gate insulator on the gate bias instability of a-InGaZnO thin film transistors in flexible electronics applications. Although the quality of SiNx at low process/deposition temperature is better than that of SiOx at similarly low process/deposition temperature, there is still a very large positive threshold voltage (V-th) shift of 9.4 V for devices with a single low-temperature SiNx gate insulator under positive gate bias stress. However, a suitable oxide-nitride-oxide-stacked gate insulator exhibits a Vth shift of only 0.23 V. This improvement results from the larger band offset and suitable gate insulator thickness that can effectively suppress carrier trapping behavior. (C) 2015 Elsevier B.V. All rights reserved.
Polymorphism Control of Layered MoTe2 through Two-Dimensional Solid-Phase Crystallization
(2019-06-19)
Huang, Jyun-Hong
;
Hsu, Hao-Hua
;
Wang, Ding
;
Lin, Wei-Ting
;
Cheng, Chun-Cheng
Two-dimensional (2D) molybdenum ditelluride (MoTe2) exhibits an intriguing polymorphic nature, showing stable semiconducting 2H and metallic 1T' phases at room temperature. Polymorphism in MoTe2 presents new opportunities in developing phase-change memory, high- performance transistors, and spintronic devices. However, it also poses challenges in synthesizing homogeneous MoTe2 with a precisely controlled phase. Recently, a new yet simple method using sputtering and 2D solid-phase crystallization (SPC) is proposed for synthesizing high-quality and large-area MoTe2. This study investigates the polymorphism control of MoTe2 synthesis using 2D SPC. The Te/Mo ratio and oxygen content in the as-sputtered films correlate strongly with the final phase and electrical properties of SPC MoTe2. Furthermore, the SPC thermal budget may be exploited for stabilizing a deterministic phase. The comprehensive experiments presented in this work demonstrate the versatile and precise controllability on the MoTe2 phase by using the simple 2D SPC technique.
The effects of gallium on solution-derived indium oxide-based thin film transistors manufactured on display glass
(2015-01-01)
Choi, Chang-Ho
;
Su, Yu-Wei
;
Lin, Liang-Yu
;
Cheng, Chun-Cheng
;
Chang, Chih-hung
Metal oxide semiconductor TFTs have been considerably investigated as a promising alternative to hydrogenated amorphous silicon and organic semiconductors. While many multicomponent oxide TFTs have been studied, there are only a few reports of TFTs using amorphous indium gallium oxide channel layers. In this study, the effects of gallium atomic ratio on the performance of solution-derived indium oxide-based TFTs on display glass were investigated for the first time. The morphological, optical, and electrical properties of IGO channel layers with different gallium atomic ratios were characterized. IGO TFTs with various chemical compositions were compared and interpreted based on the analysis of In3d, Ga2p, and O1s XPS data. It was found that gallium dopant suppresses the generation of oxygen vacancies, while promoting the formation of oxygen in the oxide lattice without oxygen vacancies by reducing the density of hydroxides. By adjusting the atomic ratio of gallium, we were able to fabricate IGO TFTs on display glass with an average field-effect mobility as high as 6.1 cm(2) V-1 s(-1), V-on = -2 V, and on-off ratio of 10(7).