Browsing by Author "You, Hsin-Chiang"

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A Robust Data Retention Characteristic of Sol-Gel-Derived Nanocrystal Memory by Hot-Hole Trapping
(2010-07-01)
Wu, Chi-Chang
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Ko, Fu-Hsiang
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Yang, Wen-Luh
;
You, Hsin-Chiang
;
Liu, Fu-Ken
A new sol-gel-derived Ti(x)Zr(y)Si(z)O nanocrystal (NC) memory with a high-performance data retention characteristic is demonstrated by the hot-hole-trapping method. Prior to rapid thermal annealing, the high-density NC layer is formed by depositing a well-mixed solution of titanium tetrachloride, silicon tetrachloride, and zirconium tetrachloride. The electrical properties of the sol-gel-derived NC memory are demonstrated in terms of memory window, charge retention, program speed, and endurance. The memory window of the NC memory from the novel hot-hole-trapping mechanism can be achieved up to 4.18 +/- 0.21 V, and long retention times obtained from extrapolation up to 10(6) s are observed as 8%, 13%, and 21% window narrowing under respective temperatures of 25 degrees C, 85 degrees C, and 125 degrees C. The good electrical performance is attributed to the contribution of the high density of isolated NCs and hole-trapped into the deep-trap energy level, so no significant lateral and vertical charge leakage occurs.
Advanced Cu chemical displacement technique for SiO2-based electrochemical metallization ReRAM application
(2014-10-28)
Chin, Fun-Tat
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Lin, Yu-Hsien
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You, Hsin-Chiang
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Yang, Wen-Luh
;
Lin, Li-Min
This study investigates an advanced copper (Cu) chemical displacement technique (CDT) with varying the chemical displacement time for fabricating Cu/SiO2-stacked resistive random-access memory (ReRAM). Compared with other Cu deposition methods, this CDT easily controls the interface of the Cu-insulator, the switching layer thickness, and the immunity of the Cu etching process, assisting the 1-transistor-1-ReRAM (1T-1R) structure and system-on-chip integration. The modulated shape of the Cu-SiO2 interface and the thickness of the SiO2 layer obtained by CDT-based Cu deposition on SiO2 were confirmed by scanning electron microscopy and atomic force microscopy. The CDT-fabricated Cu/SiO2-stacked ReRAM exhibited lower operation voltages and more stable data retention characteristics than the control Cu/SiO2-stacked sample. As the Cu CDT processing time increased, the forming and set voltages of the CDT-fabricated Cu/SiO2-stacked ReRAM decreased. Conversely, decreasing the processing time reduced the on-state current and reset voltage while increasing the endurance switching cycle time. Therefore, the switching characteristics were easily modulated by Cu CDT, yielding a high performance electrochemical metallization (ECM)-type ReRAM.
COLL 327-Sol-gel synthesis and surface reaction of oxygen plasma for flexible metal-insulator-metal devices
(2009-08-16)
Chu, Min-Ching
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Lin, Ching-Chang
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You, Hsin-Chiang
;
Ko, Fu-Hsiang
;
材料科學與工程學系奈米科技碩博班
Controllable Ink-Jet Printing Technique on Various Channel Width Designs Toward Zinc Oxide-based Thin Film Transistor
(2016)
Wang, Cheng-Jyun
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Ko, Fu-Hsiang
;
You, Hsin-Chiang
;
Du, Bo-Wei
;
材料科學與工程學系
Ink-jet printed (IJP) thin-film transistor (TFT) electronics employing solution processed materials is considered to be the key technique to achieve mask-less, low-cost, large-area, and low temperature fabrication systems. We propose an approach for a direct printing highly transparent conducting oxide material of zinc oxide (ZnO) which the use of semiconductor layer with different transistor channel widths without any photolithography process defined. In this work, we describe the ink-jet printing ZnO TFT with three-types channel widths, and electrical characteristics with low voltage operation, high performance of switch on/off state and low temperature fabrication (200 similar to 300 degrees C). These printed TFT thus represent an uniquely attractive path for realizing high flexibility printed electronics.
Effect of oxygen plasma on the surface states of ZnO films used to produce thin-film transistors on soft plastic sheets
(2013)
Meena, Jagan Singh
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Chu, Min-Ching
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Chang, Yu-Cheng
;
You, Hsin-Chiang
;
Singh, Ranjodh
Electronic displays and flexible electronics are poised to significantly impact emerging industries, including displays, energy products, sensors and medical devices, building a market that will significantly grow in the future. The implementation of transparent electronic devices requires the use of material components that could be formed using controlled deposition in the appropriate orientation onto a transparent flexible substrate. Here, we report a simple and efficient means of depositing onto a flexible polyimide (PI) substrate a highly ordered and highly aligned zinc oxide (ZnO) film for use as a carrier transporting and semiconducting layer with controlled surface charge density for thin-film transistor (TFT) applications. The deposition approach is based on the solution-coating of a zinc-acetate suspension under controlled conditions of the spread flow rate, droplet size of the drops, speed limit, and the oxygen (ca. O-2) plasma treatment of the coated film surface on the PI substrate. The plasma surface interactions on the surface states of the ZnO films for various times (ca. 1-5 min) were studied using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Moreover, the effects of O-2 plasma and the subsequent thermal annealing in an O-2 atmosphere at 250 degrees C on the properties of ZnO films were studied for its efficacy in TFT applications in terms of the charge carrier density and the change in the mobility. ZnO thin-film-based TFTs on PI exhibited a very high electron mobility of 22.8 cm(2) V-1 s(-1) at a drain bias of 5 V after treatment with O-2 plasma for 2 min. Furthermore, the plasma treatment for long durations of time caused a reduction in the charge carrier density from 1.58 x 10(19) cm(-3) for the 2 min treatment to 1.13 x 10(17) cm(-3) for the 5 min treatment, and the corresponding electron mobility was changed from 22.8 and 3.1 cm(2) V-1 s(-1) for the treatment times of 2 min and 5 min, respectively. The spin-coating technique used to deposit very thin ZnO films is currently used in microelectronics technology, which helps to ensure that the described ZnO thin-film deposition approach can be implemented in production lines with minimal changes in the fabrication design and in the auxiliary tools used in flexible electronics production.
Fabrication of SONOS-type flash memory with the binary high-k dielectrics by the sol-gel spin coating method
(2007)
Ko, Fu-Hsiang
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You, Hsin-Chiang
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Chang, Chun-Ming
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Yang, Wen-Luh
;
Lei, Tan-Fu
We fabricated the binary high-k (HfxZr1-xO2) nanocrystal memory using a very simple sol-gel spin coating method and 900 degrees C 60 s rapid thermal annealing (RTA). From the transmission electron microscopy identification, the nanocrystals were formed as the monolayered charge trapping site after 900 degrees C 60 s RTA and the size was ca. 5 nm. We verified the electrical properties in terms of program-erase speed, charge retention, and endurance. The sol-gel device exhibited the long charge retention time of 10(4) s with only 2.5% charge loss, and good endurance performance for program/erase cycles up to 10(5). (c) 2007 The Electrochemical Society.
Facile Electroless Deposition of Zinc Oxide Ultrathin Film for Zinc Acetate Solution-processed Transistors
(2012-07-01)
Chu, Min-Ching
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You, Hsin-Chiang
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Meena, Jagan Singh
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Shieh, Shao-Hui
;
Shao, Chyi-Yau
"A low-cost, ultra-thin, transparency and high-quality zinc oxide (ZnO) film was successfully demonstrated as the carrier transporting and semiconducting layer for thin-film transistor (TFT) devices. The ZnO ultra-thin film with 3.7 nm in thickness was spin-coated from zinc acetate sol-gel solution under electroless condition. The film structure was characterized by atomic force microscopy and x-ray diffraction spectroscopy, respectively. Among various processing temperatures, the electrical property of the fabricated TFT verified the devices could be successfully achieved from suitable annealing temperature of 300 to 700 degrees C. However, the higher treatment temperature of 800 to 900 degrees C deteriorated the transistor property due to the loss of oxygen vacancy. The electrical properties of these ZnO-based n-type TFTswere obtained as follows: the mobility (mu(sat))ranged from 0.47 to 1.78 cm(2) V-1 s(-1), the on/off current ratio ranged from 5.7 x 10(5) to 1.6 x 10(6), and the threshold voltage ranged from 9.7 to 17.3 V. The long-term (100 days) characterization for the evaluation of the ultra-thin ZnO TFT reliability on the mobility and on/off current ratio strongly suggested the effectiveness of solution-processed ultra-thin film transistors. This proposed efficient sol-gel solution method to fabricate transparent ZnO ultra-thin film was relatively simple and cost-effective technique, and could be used as a new candidate of material for next-generation electronic devices to meet the growing demand of small feature bioelectronic sensor, light emitting diode and flexible panel."
Facile preparation of sol-gel-derived ultrathin and high-dielectric zirconia films for capacitor devices
(2012-10-01)
You, Hsin-Chiang
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Chang, Chun-Ming
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Liu, Tzeng-Feng
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Cheng, Chih-Chia
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Chang, Feng-Chih
This study successfully prepared zirconia ultrathin films from the sol-gel solution with dispersion of zirconium halide in 1-octanol solvent. The film was subjected to annealing treatments after sol-gel spin-coating, and the films of interest were evaluated. The amorphous morphology of the zirconia film was identified using high-resolution transmission electron microscopy and X-ray diffractometry. The plot of the current density with respect to the electric field demonstrates that the as-deposited film at 500 degrees C annealing exhibited an inferior leakage current, whereas 600 degrees C annealing stabilized the film with a satisfactory leakage current of 10(-8) to 10(-9) A/cm(2). The out-gassing behavior of the sol-gel-derived thin film was evaluated using a thermal desorption system, that is, atmospheric pressure ionization mass spectrometry. The dielectric constant of the film was dependent on the retention effect of the preparation solvents. The low residual solvent for the preparation of the thin film with 1-octanol solvent and 600 degrees C annealing contributed to the superior high-k property. (C) 2012 Elsevier B.V. All rights reserved.
Flexible metal-insulator-metal capacitor using plasma enhanced binary hafnium-zirconium-oxide as gate dielectric layer
(2010-05-01)
Meena, Jagan Singh
;
Chu, Min-Ching
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Tiwari, Jitendra N.
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You, Hsin-Chiang
;
Wu, Chung-Hsin
We have used a sol-gel spin-coating process to fabricate a new metal-insulator-metal capacitor comprising 10-nm thick binary hafnium-zirconium-oxide (Hf(x)Zr(1-x)O(2)) film on a flexible polyimide (PI) substrate. The surface morphology of this Hf(x)Zr(1-x)O(2) film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the PI. After oxygen plasma pre-treatment and subsequent annealing at 250 degrees C, the film on the PI substrate exhibited a low leakage current density of 3.22 x 10(-8) A/cm(2) at -10 V and maximum capacitance densities of 10.36 fF/mu m(2) at 10 kHz and 9.42 fF/mu m(2) at 1 MHz. The as-deposited sol-gel film was oxidized when employing oxygen plasma at a relatively low temperature (similar to 250 degrees C), thereby enhancing the electrical performance. (C) 2010 Elsevier Ltd. All rights reserved.
Hafnium silicate nanocrystal memory using sol-gel-spin-coating method
(2006-08-01)
You, Hsin-Chiang
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Hsu, Tze-Hsiang
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Ko, Fu-Hsiang
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Huang, Jiang-Wen
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Lei, Tan-Fu
The authors fabricate the hafnium silicate nanocrystal memory for the first time using a very simple sol-gel-spincoating method and 900 degrees C 1-min rapid thermal annealing (RTA). From the TEM identification, the nanocrystals are formed as the charge trapping layer after 900 degrees C 1-min RTA and the size is about 5 mn. They demonstrate the composition of nanocrystal is hafnium silicate from the X-ray-photoelectron-spectroscopy analysis. They verify the electric properties in terms of program/erase (P/E) speed, charge retention, and endurance. The sol-gel device exhibits the long charge retention time of 10(4) s with only 6% charge loss, and good endurance performance for P/E cycles up to 10(5).
HfO2 Trap Layer Nonvolatile Flash Memory on SiGe Channel
(2014-01-01)
Lin, Yu-Hsein
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Li, Jyun-Han
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You, Hsin-Chiang
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Hong, Jin-Shi
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Tsai, Wan-Ting
This paper study a novel nonvolatile memory by using HfO2 trapping layer on epi-SiGe (Ge: 15%) channel. Because SiGe has a smaller bandgap than that of silicon, it can increases the electron/hole injection and enhances the program/erase speed. This study compares the characteristics of HfO2 memories with different tunnel oxynitride thicknesses on epi-SiGe substrate. The results show that the nonvolatile memory has superior characteristics in terms of considerably large memory window, high speed program/erase, long retention time, good endurance for future low power applications.
Highly Transparent and Surface-Plasmon-Enhanced Visible-Photodetector Based on Zinc Oxide Thin-Film Transistors with Heterojunction Structure
(2019-11-01)
Wang, Cheng-Jyun
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You, Hsin-Chiang
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Lin, Kuan
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Ou, Jen-Hung
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Chao, Keng-Hsien
Highly transparent zinc oxide (ZnO)-based thin-film transistors (TFTs) with gold nanoparticles (AuNPs) capable of detecting visible light were fabricated through spray pyrolysis on a fluorine-doped tin oxide substrate. The spray-deposited channel layer of ZnO had a thickness of approximately 15 nm, and the thickness exhibited a linear increase with an increasing number of sprays. Furthermore, the ZnO thin-film exhibited a markedly smoother channel layer with a significantly lower surface roughness of 1.84 nm when the substrate was 20 cm from the spray nozzle compared with when it was 10 cm away. Finally, a ZnO and Au-NP heterojunction nanohybrid structure using plasmonic energy detection as an electrical signal, constitutes an ideal combination for a visible-light photodetector. The ZnO-based TFTs convert localized surface plasmon energy into an electrical signal, thereby extending the wide band-gap of materials used for photodetectors to achieve visible-light wavelength detection. The photo-transistors demonstrate an elevated on-current with an increase of the AuNP density in the concentration of 1.26, 12.6, and 126 pM and reach values of 3.75, 5.18, and 9.79 x 10(-7) A with applied gate and drain voltages. Moreover, the threshold voltage (Vth) also drifts to negative values as the AuNP density increases.
Nanocrystallization and interfacial tension of sol-gel derived memory
(2008-03-24)
Wu, Chi-Chang
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Tsai, Yi-Jen
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Chu, Min-Ching
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Yang, Shao-Ming
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Ko, Fu-Hsiang
The formation of the nanocrystals (NCs) by using the sol-gel spin-coating method at various annealing temperatures had been studied. The film started to form the islands at 600 degrees C annealing, and finally transferred into NCs at 900 degrees C. A model was proposed to explain the transformation of thin film. The morphology of sol-gel thin film at 600 degrees C annealing was varied and had higher interfacial energy. The crystallized process at 900 degrees C annealing could minimize the energy. The retention for 900 degrees C annealed sample exhibited less than 30% charge loss after 10(6) s at 125 degrees C measurement. (c) 2008 American Institute of Physics.
Novel coexisted sol-gel derived poly-Si-oxide-nitride-oxide-silicon type memory
(2007-11-01)
You, Hsin-Chiang
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Wu, Chi-Chang
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Ko, Fu-Hsiang
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Lei, Tan-Fu
;
Yang, Wen-Luh
The authors use a very simple sol-gel spin coating method at 900 degrees C and 1 min rapid thermal annealing to fabricate three different poly-Si-oxide-nitride-oxide-silicon-type flash memories. The memory windows estimated from the curve of drain current versus applied gate voltage are 3, 3.3, and 4 V for (i) HfO2 thin film, (ii) hafnium silicate nanocrystal, and (iii) coexisted hafnium silicate and zirconium silicate nanocrystal memory, respectively. Together with the measurement from gate disturbance and drain disturbance on these fabricated devices, the coexisted nanocrystal devices exhibit better reliability than both the thin film type memory and single nanocrystal type memory. (C) 2007 American Vacuum Society.
Novel Sol-gel Derived SONOS-type Nanocrystal Memory
(2010)
Wu, Chi-Chang
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You, Hsin-Chiang
;
Ko, Fu-Hsiang
;
Yang, Wen-Luh
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材料科學與工程學系奈米科技碩博班
A nanocrystal (NC) memory by sol-gel spin-coating method was demonstrated. The high-density and isolated NC was formed by depositing a mixed solution of nickel tetrachloride, zirconium tetrachloride, silicon tetrachloride, and germanium tetrachloride with a post-rapid thermal annealing process. The electrical properties in terms of memory window, charge retention, program/erase speed, and endurance were demonstrated. The memory window of the NC memory can be up to 2.8 V: the retention times were extrapolated up to 10(6) sec for about 5% and 10% charge loss at 25 and 85 degrees C measurement, respectively. The voltage shift after 10(4) program/erase cycles is less than 1V. The good electrical performance was attributed to the effects of the high-density isolated NCs.
Oxygen Plasma Functioning of Charge Carrier Density in Zinc Oxide Thin-Film Transistors
(2013-07-01)
Chu, Min-Ching
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Meena, Jagan Singh
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Liu, Po-Tsun
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Shieh, Han-Ping D.
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You, Hsin-Chiang
A change in the charge carrier density of zinc oxide (ZnO) films for control the functioning of thin-film transistors (TFTs) has been studied by oxygen (O-2) plasma techniques. This effect was interpreted in terms of a threshold voltage shift and the variation in carrier mobility. The plasma-surface interaction on the molecular level and the behavioral characterization of ZnO films were investigated by X-ray photospectroscopy of the O 1s region. This process was highly sensitive at low level variations in defect and doping density. O-2 plasma treatment leads to a shift of turn-on voltage and a reduction of the off-current by more than two orders of magnitude in ZnO-TFTs. (C) 2013 The Japan Society of Applied Physics
Plasma-enhanced flexible metal-insulator-metal capacitor using high-k ZrO(2) film as gate dielectric with improved reliability
(2010-08-01)
Chu, Min-Ching
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Meena, Jagan Singh
;
Cheng, Chih-Chia
;
You, Hsin-Chiang
;
Chang, Feng-Chih
We demonstrate a new flexible metal-insulator-metal capacitor using 9.5-nm-thick ZrO(2) film on a plastic polyimide substrate based on a simple and low-cost sal-gel precursor spin-coating process. The surface morphology of the ZrO(2) film was investigated using scan electron microscope and atomic force microscope. The as-deposited ZrO(2) film under suitable treatment of oxygen (O(2)) plasma and then subsequent annealing at 250 degrees C exhibits superior low leakage current density of 9.0 x 10(-9) A/cm(2) at applied voltage of 5 V and maximum capacitance density of 13.3 fF/mu m(2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when we employed O(2) plasma at relatively low temperature and power (30 W), hence enhancing the electrical performance of the capacitor. The shift (Zr 3d from 184.1 eV to 184.64 eV) in X-ray photoelectron spectroscopy of the binding energy of the electrons towards higher binding energy; clearly indicates that the O(2) plasma reaction was most effective process for the complete oxidation of the sol-gel precursor at relatively low processing temperature. (C) 2010 Elsevier Ltd. All rights reserved.
Plasma-enhanced flexible metal-insulator-metal capacitor using high-k ZrO2 film as gate dielectric with improved reliability
(2010-08-01)
Chu, Min-Ching
;
Meena, Jagan Singh
;
Cheng, Chih-Chia
;
You, Hsin-Chiang
;
Chang, Feng-Chih
We demonstrate a new flexible metal-insulator-metal capacitor using 9.5-nm-thick ZrO2 film on a plastic polyimide substrate based on a simple and low-cost sal-gel precursor spin-coating process. The surface morphology of the ZrO2 film was investigated using scan electron microscope and atomic force microscope. The as-deposited ZrO2 film under suitable treatment of oxygen (O-2) plasma and then subsequent annealing at 250 degrees C exhibits superior low leakage current density of 9.0 x 10(-9) A/cm(2) at applied voltage of 5 V and maximum capacitance density of 13.3 fF/mu m(2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when we employed O-2 plasma at relatively low temperature and power (30 W), hence enhancing the electrical performance of the capacitor. The shift (Zr 3d from 184.1 eV to 184.64 eV) in X-ray photoelectron spectroscopy of the binding energy of the electrons towards higher binding energy; clearly indicates that the O-2 plasma reaction was most effective process for the complete oxidation of the sol-gel precursor at relatively low processing temperature. (C) 2010 Elsevier Ltd. All rights reserved.
PolySi-SiO2-ZrO2-SiO2-Si flash memory incorporating a sol-gel-derived ZrO2 charge trapping layer
(2006)
Hsu, Tzu-Hsiang
;
You, Hsin-Chiang
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Ko, Fu-Hsiang
;
Lei, Tan-Fu
;
材料科學與工程學系奈米科技碩博班
In this paper, we propose a method for depositing the charge trapping layer of a high-k polySi-SiO2-ZrO2-SiO2-Si (SOZOS) memory device. In this approach, the trapping layer was formed through simple two steps: (i) spin-coating of the ZrCl4 precursor and (ii) rapid thermal annealing for 1 min at 900 C under an oxygen atmosphere. The morphology of the ZrO2 charge trapping layer was confirmed through X-ray photoemission spectroscopy analysis. The sol-gel-derived layer exhibited improved charge trapping in the SOZOS memory device, resulting in a threshold voltage shift of 2.7 V in the I-d-V-g curve, P/E (program/erase) speeds as fast as 0.1 ms, good data retention up to 10(4) s (only a 5% charge loss due to deep trapping in the ZrO2 layer), and good endurance (no memory window narrowing after 10(5) P/E cycles). (c) 2006 The Electrochemical Society.
Polystyrene-block-poly(methylmethacrylate) composite material film as a gate dielectric for plastic thin-film transistor applications
(2014)
Meena, Jagan Singh
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Chu, Min-Ching
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Singh, Ranjodh
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Wu, Chung-Shu
;
Chand, Umesh
We report a simple approach to fabricate an organic-inorganic hybrid gate insulator based n-type thin-film transistor (TFT) on a plastic polyimide (PI) sheet at room temperature using an appropriate composition of commercially available polymers and block copolymer surfactant. The composite material film namely; polystyrene-block-poly(methylmethacrylate) (PS-b-PMMA) is readily deposited as a gate dielectric with zinc oxide (ZnO) as a semiconductor layer. This new dielectric material film exhibits high surface energy, high air stability, very low leakage current density and better dielectric constant as compared to the conventional polymer dielectrics. This plastic ZnO-TFT combines the advantages of a high-mobility transparent inorganic semiconductor with an ultrathin high-capacitance and low-leakage PS-b-PMMA composite gate dielectric. Fourier transform infrared (FT-IR) spectrum analysis is used for the PS-b-PMMA film to confirm the presence of functional components in this composite material film. The contact angle measurements for three test liquids (e.g., distilled water, ethylene glycol and diiodomethane) reveal that the composite dielectric materials film is nearly hydrophobic and the calculated surface energy is 35.05 mJ m(-2). The resulting TFT exhibits excellent operating characteristics at V-DS=10 V with a drain-source current on/off modulation ratio (I-on/I-off) of 3.12 x 10(6) and a carrier mobility of 2.48 cm(2) V-1 s(-1). Moreover in the bending mode and in a normal environment, the device remained undistorted and shows better reliability and performance, while the thickness of PS-b-PMMA is about 28 nm. The results have suggested a new and easy approach for achieving transparent and functionally bendable optoelectronics devices.