Browsing by Author "Chang, Geng-Wei"

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Abnormal Subthreshold Leakage Current at High Temperature in InGaZnO Thin-Film Transistors
(2012-04-01)
Chang, Geng-Wei
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Chang, Ting-Chang
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Jhu, Jhe-Ciou
;
Tsai, Tsung-Ming
;
Syu, Yong-En
Abnormal subthreshold leakage current is observed at high temperature in amorphous InGaZnO thin-film transistors. The transfer curve exhibits an apparent subthreshold current stretch-out phenomenon that becomes more serious with increasing temperatures. The negative bias temperature instability experiment has been used to prove high-temperature-induced hole generation. Furthermore, the transfer characteristics with different drain voltages have been also used to confirm the status of hole accumulation. These pieces of evidence clearly defined the stretch-out phenomenon, which is caused by thermal-induced hole generation and accumulation at the source region that leads to source-side barrier lowering.
Asymmetric Carrier Conduction Mechanism by Tip Electric Field in WSiOX Resistance Switching Device
(2012-03-01)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Tsung-Ming
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Chang, Geng-Wei
;
Chang, Kuan-Chang
Resistance random access memory (RRAM) is a great potential candidate for next-generation nonvolatile memory due to the outstanding memory characteristic. However, the resistance switching mechanism is still a riddle nowadays. In this letter, the switching mechanism is investigated by current-voltage (I-V) curve fitting in the TiN/WSiOX/Pt RRAM device. The asymmetric phenomenon of the carrier conduction behavior is explained at the high-resistance state in high electric field. The switching behavior is regarded to tip electric field by localizing the filament between the interface of top electrode and insulator.
Bipolar Resistive RAM Characteristics Induced by Nickel Incorporated Into Silicon Oxide Dielectrics for IC Applications
(2012-12-01)
Tsai, Tsung-Ming
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Chang, Kuan-Chang
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Chang, Ting-Chang
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Syu, Yong-En
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Chuang, Siang-Lan
In this letter, we successfully produced resistive switching behaviors by nickel doped into silicon oxide at room temperature. The nickel element was doped into silicon oxide, which is a useful dielectric material in integrated circuit (IC) industries by cosputtering technology. Based on the proposed method, satisfactory reliability of the resistance switching device can be demonstrated by endurance and retention evaluation. We believe that the silicon oxide doped with nickel at room temperature is a promising method for resistive random access memory nonvolatile memory applications due to its compatibility with the IC processes.
Characteristics and Mechanisms of Silicon-Oxide-Based Resistance Random Access Memory
(2013-03-01)
Chang, Kuan-Chang
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Tsai, Tsung-Ming
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Chang, Ting-Chang
;
Wu, Hsing-Hua
;
Chen, Jung-Hui
Traditionally, a large number of silicon oxide materials are extensively used as various dielectrics for semiconductor industries. In general, silicon oxide cannot be used as resistance random access memory (RRAM) due to its insulating electrical properties. In this letter, we have successfully produced resistive switching and forming-free behaviors by zinc doped into silicon oxide. The current-voltage fitting data show that current transport mechanism is governed by Poole-Frenkel behavior in high-resistance state and Ohm's law in low-resistance state, consisting with filament theory. Additionally, good endurance and retention reliabilities are exhibited in the zinc-doped silicon oxide RRAM.
Charge Quantity Influence on Resistance Switching Characteristic During Forming Process
(2013-04-01)
Chu, Tian-Jian
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Chang, Ting-Chang
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Tsai, Tsung-Ming
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Wu, Hsing-Hua
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Chen, Jung-Hui
In this letter, we presented that the charge quantity is the critical factor for forming process. Forming is a pivotal process in resistance random access memory to activate the resistance switching behavior. However, overforming would lead to device damage. In general, the overshoot current has been considered as a degradation reason during the forming process. In this letter, the quantity of charge through the switching layer has been proven as the key element in the formation of the conduction path. Ultrafast pulse forming can form a discontinuous conduction path to reduce the operation power.
Effect of Lateral Body Terminal on Silicon-Oxide-Nitride-Oxide-Silicon Thin-Film Transistors
(2011-10-01)
Li, Hung-Wei
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Chang, Ting-Chang
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Chang, Geng-Wei
;
Lin, Chia-Sheng
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Tsai, Tsung-Ming
We investigate lateral-body-terminal silicon-oxide-nitride-oxide-silicon thin-film transistors (LBT SONOS TFTs) under erasing operation. These devices have superior erasing efficiency by gate as well as lateral body electrode exerting bias. The erasing mechanism of LBT SONOS TFTs has been illustrated by the energy band diagrams. Holes gain sufficient energy by the electric field in the deep-depletion region to surmount the tunneling oxide barrier because of exerting body bias under erasing operation. In addition, the lateral body terminal exerting bias can enhance the erasing efficiency and is confirmed by different erasing conditions and structures. In addition, to verify the hole current injecting from the lateral body site, the size effect of LBT SONOS TFTs is also discussed.
Improvement mechanism of resistance random access memory with supercritical CO2 fluid treatment
(2014-01-01)
Chang, Kuan-Chang
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Chen, Jung-Hui
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Tsai, Tsung-Ming
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Chang, Ting-Chang
;
Huang, Syuan-Yong
We demonstrated that the supercritical CO2 fluid treatment was a new concept to efficiently reduce the operation current of resistance random access memory. The dangling bonds of tin-doped silicon oxide (Sn:SiOx) thin film were passivated by the hydration-dehydration reaction through supercritical CO2 fluid treatment, which was verified by the XPS and FTIR analyses. The current conduction mechanism of low resistance state in post-treated Sn:SiOx thin film was transferred to hopping conduction from Ohmic conduction. Furthermore, the current conduction mechanism of high resistance state in the memory device was transferred to Schottky emission from Frenkel-Poole conduction. The phenomena were attributed to the discontinuous metal filament formed by hydration-dehydration reaction in Sn:SiOx thin film through supercritical fluid treatment. Finally, a reaction model was proposed to explain the mechanism of current reduction in Sn:SiOx thin film with supercritical CO2 fluid treatment. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
Improving Resistance Switching Characteristics with SiGeO(x)/SiGeON Double Layer for Nonvolatile Memory Applications
(2011-01-01)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Chih-Tsung
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Chang, Geng-Wei
;
Tsai, Tsung-Ming
The switching layer with SiGeO(x)/SiGeON structure is investigated to improve the electrical characteristics of resistive nonvolatile memory. A bipolar resistance switching behavior owning inferior stability was observed in Pt/SiGeO(x)/TiN memory cells. To obtain practical memory, a convenient and compatible SiGeON (similar to 5 nm) is introduced at SiGeO(x)/anode interface to stabilize the disruption length of filaments near anode electrode. Compared with Pt/SiGeO(x)/TiN memory cells, the proposed Pt/SiGeO(x)/SiGeON/TiN cells is effective at minimizing the dispersions of memory switching parameters. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615823] All rights reserved.
Improving Resistance Switching Characteristics with SiGeOx/SiGeON Double Layer for Nonvolatile Memory Applications
(2011-01-01)
Syu, Yong-En
;
Chang, Ting-Chang
;
Tsai, Chih-Tsung
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Chang, Geng-Wei
;
Tsai, Tsung-Ming
The switching layer with SiGeOx/SiGeON structure is investigated to improve the electrical characteristics of resistive nonvolatile memory. A bipolar resistance switching behavior owning inferior stability was observed in Pt/SiGeOx/TiN memory cells. To obtain practical memory, a convenient and compatible SiGeON (similar to 5 nm) is introduced at SiGeOx/anode interface to stabilize the disruption length of filaments near anode electrode. Compared with Pt/SiGeOx/TiN memory cells, the proposed Pt/SiGeOx/SiGeON/TiN cells is effective at minimizing the dispersions of memory switching parameters. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615823] All rights reserved.
Low Temperature Improvement Method on Zn:SiOx Resistive Random Access Memory Devices
(2013-04-01)
Chang, Kuan-Chang
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Tsai, Tsung-Ming
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Chang, Ting-Chang
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Wu, Hsing-Hua
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Chen, Kai-Huang
To improve the resistive switching properties of the resistive random access memory (RRAM), the supercritical carbon dioxide (SCCO2) fluid is used as a low temperature treatment. In this letter, the Zn:SiOx thin films are treated by SCCO2 fluid mixed with pure water. After SCCO2 fluid treatment, the resistive switching qualities of the Zn:SiOx thin films are carried out by XPS, fourier transform infrared spectroscopy, and IV measurement. We believe that the SCCO2-treated Zn:SiOx thin film is a promising material for RRAM applications due to its compatibility with portable flat panel display.
N2O Plasma Treatment Suppressed Temperature-dependent Point Defects Formation with Amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors
(2012)
Jhu, Jhe-Ciou
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Chang, Ting-Chang
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Chang, Geng-Wei
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Syu, Yong-En
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Tsai, Tsung-Ming
Abnormal sub-threshold leakage current is observed at high temperature in amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors (a-IGZO TFTs). To confirm this phenomenon\'s dependence on the defects of a-IGZO active layer, this paper examines a device fabricated with N2O plasma treatment at a-IGZO film. This phenomenon only appears in the as-fabricated device, but not in the device with N2O plasma treatment, which is experimentally verified. N2O plasma treatment of a-IGZO TFTs enhance the thin film bonding strength, which could suppress the formation of temperature-dependent point defects. The point defects could be generated from oxygen atoms leaving their original sites above 400K. The N2O plasma treatment devices have better stability performance than as-fabricated devices. The results suggested that the density of point states for a-IGZO TFTs with N2O plasma treatment is much lower than that as-fabricated. The N2O plasma repairs the point defect to suppress temperature-dependent sub-threshold leakage current.
N2O plasma treatment suppressed temperature-dependent sub-threshold leakage current of amorphous indium-gallium-zinc-oxide thin film transistors
(2013-09-01)
Chang, Geng-Wei
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Chang, Ting-Chang
;
Jhu, Jhe-Ciou
;
Tsai, Tsung-Ming
;
Syu, Yong-En
N2O plasma treatment suppressed the temperature-dependent sub-threshold leakage current of amorphous indium-gallium-zinc-oxide thin film transistors (a-IGZO TFTs). For untreated devices, the transfer curve exhibited abnormal electrical properties at high temperature. The abnormal electrical properties are explained by the energy band diagrams for both forward and reverse sweep. Above 400 K, holes can be generated from trap-assisted transition, and drift to the source side which induces source barrier lowering. The source side barrier lowering enhances electron injection from the source to channel and causes an apparent sub-threshold leakage current. This phenomenon, which is experimentally verified, only appears in the device without N2O plasma treatment, but not in the device with N2O plasma treatment. The results suggested that the density of states for a-IGZO with N2O plasma treatment is much lower than that without plasma treatment. (C) 2012 Elsevier B.V. All rights reserved.
On-Current Decrease After Erasing Operation in the Nonvolatile Memory Device With LDD Structure
(2011-08-01)
Chang, Geng-Wei
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Chang, Ting-Chang
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Syu, Yong-En
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Tai, Ya-Hsiang
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Jian, Fu-Yen
The on-current decrease phenomenon is observed after erasing operation in the silicon-oxide-nitride-oxide-silicon thin-film transistors (TFTs) with lightly doped drain (LDD) structure. As nonvolatile memory, when the TFT is programmed again, the on-current decrease phenomenon can be recovered. The on-current decrease and recovery are explained by the energy band diagrams at different drain biases. The explanation implies that this phenomenon only appears in the device with LDD structure, but not in the device without LDD structure, which is experimentally verified.
Origin of Hopping Conduction in Graphene-Oxide-Doped Silicon Oxide Resistance Random Access Memory Devices
(2013-05-01)
Chang, Kuan-Chang
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Zhang, Rui
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Chang, Ting-Chang
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Tsai, Tsung-Ming
;
Lou, J. C.
In this letter, a double-active-layer (Zr:SiOx/C:SiOx) resistive switching memory device with a high ON/OFF resistance ratio and small working current (0.02 mA), is presented. Through the analysis of Raman and Fourier transform infrared spectroscopy spectra, we find that graphene oxide exists in the C:SiOx layer. It can be observed that Zr:SiOx/C: SiOx structure has superior switching performance and higher stability compared with the single-active-layer (Zr:SiOx) structure, which is attributed to the existence of graphene oxide flakes formed during the sputter process. I-V characteristics under a series of increasing temperature were analyzed to testify the carrier hopping distance variation, which is further verified by our graphene oxide redox reaction model.
Origin of Hopping Conduction in Sn-Doped Silicon Oxide RRAM With Supercritical CO2 Fluid Treatment
(2012-12-01)
Tsai, Tsung-Ming
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Chang, Kuan-Chang
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Chang, Ting-Chang
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Chang, Geng-Wei
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Syu, Yong-En
In this letter, we investigate the origin of hopping conduction in the low-resistance state (LRS) of a resistive random access memory device with supercritical CO2 fluid treatment. The dangling bonds of a tin-doped silicon oxide (Sn:SiOx) thin film were cross linked by the hydration-dehydration reaction through supercritical fluid technology. The current conduction mechanism of the LRS in the posttreated Sn:SiOx thin film was transferred to hopping conduction from Ohmic conduction, owing to isolation of metal tin in the Sn:SiOx thin film by hydration-dehydration reaction. The phenomena can be verified by our proposed reaction model, which is speculated by the X-ray photoelectron spectroscopy analyses.
Paraffin wax passivation layer improvements in electrical characteristics of bottom gate amorphous indium-gallium-zinc oxide thin-film transistors
(2011-12-30)
Chang, Geng-Wei
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Chang, Ting-Chang
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Syu, Yong-En
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Tsai, Tsung-Ming
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Chang, Kuan-Chang
In this research, paraffin wax is employed as the passivation layer of the bottom gate amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs), and it is formed by sol-gel process in the atmosphere. The high yield and low cost passivation layer of sol-gel process technology has attracted much attention for current flat-panel-display manufacturing. Comparing with passivation-free a-IGZO TFTs, passivated devices exhibit a superior stability against positive gate bias stress in different ambient gas, demonstrating that paraffin wax shows gas-resisting characteristics for a-IGZO TFTs application. Furthermore, light-induced stretch-out phenomenon for paraffin wax passivated device is suppressed. This superior stability of the passivated device was attributed to the reduced total density of states (DOS) including the interfacial and semiconductor bulk trap densities. (C) 2011 Elsevier B.V. All rights reserved.
Reduction of defect formation in amorphous indium-gallium-zinc-oxide thin film transistors by N2O plasma treatment
(2013-11-28)
Jhu, Jhe-Ciou
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Chang, Ting-Chang
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Chang, Geng-Wei
;
Tai, Ya-Hsiang
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Tsai, Wu-Wei
An abnormal sub-threshold leakage current is observed at high temperature in amorphous indium-gallium-zinc-oxide thin film transistors (a-IGZO TFTs). This phenomenon occurs due to a reduced number of defects in the device's a-IGZO active layer after the device has undergone N2O plasma treatment. Experimental verification shows that the N2O plasma treatment enhances the thin film bonding strength, thereby suppressing the formation of temperature-dependent holes, which are generated above 400 K by oxygen atoms leaving their original sites. The N2O plasma treatment devices have better stability performance than as-fabricated devices. The results suggest that the density of defects for a-IGZO TFTs with N2O plasma treatment is much lower than that in as-fabricated devices. The N2O plasma treatment repairs the defects and suppresses temperature-dependent sub-threshold leakage current. (C) 2013 AIP Publishing LLC.
Silicon introduced effect on resistive switching characteristics of WO(X) thin films
(2012-01-09)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Tsung-Ming
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Chang, Geng-Wei
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Chang, Kuan-Chang
The switching layer with Si interfusion is investigated to improve the electrical characteristics of WO(X) resistance random access memory (RRAM). The WO(X) has attracted extensive attention for RRAM because it can form by converting the surface of the W-plug with a current complementary metal oxide semiconductor (CMOS) compatible thermal oxidation process. In general, the resistance switching behavior of WO(X)-RRAM devices is unstable because the diverse oxidation state provided the stochastic conduction paths. In this research, the Si interfusion can effectively localize the filament conduction path in WO(X) resistance switching layer because the tungsten filament path is limited by SiO(X) in the WSiO(X) film during the forming process. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3676194]
Silicon introduced effect on resistive switching characteristics of WOX thin films
(2012-01-09)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Tsung-Ming
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Chang, Geng-Wei
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Chang, Kuan-Chang
The switching layer with Si interfusion is investigated to improve the electrical characteristics of WOX resistance random access memory (RRAM). The WOX has attracted extensive attention for RRAM because it can form by converting the surface of the W-plug with a current complementary metal oxide semiconductor (CMOS) compatible thermal oxidation process. In general, the resistance switching behavior of WOX-RRAM devices is unstable because the diverse oxidation state provided the stochastic conduction paths. In this research, the Si interfusion can effectively localize the filament conduction path in WOX resistance switching layer because the tungsten filament path is limited by SiOX in the WSiOX film during the forming process. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3676194]
Study of Resistive Switching Characteristics on a Temperature-Sensitive FeOx-Transition Layer in a TiN/SiO2/FeOx/Fe Structure
(2012)
Chang, Yao-Feng
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Tsai, Yu-Ting
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Chang, Geng-Wei
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Syu, Yong-En
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Tai, Ya-Hsiang
Thermal annealing effect and high temperature electrical measurement were studied on a temperature-sensitive FeOx-transition layer of a TiN/SiO2/FeOx/Fe structure, including bipolar switching behaviors, statistics of set and reset electrical characteristics, endurance and retention. Increase of the thermal budget on the structure shrinks both the operation voltage and variation as well as improving the device operation stability and power dissipation. Cross-sectional image, crystallinity and chemical composition analyzes of the FeOx-transition layer were examined by transmission electron microscope, X-ray diffraction and X-ray photon-emission spectra depth profiles, respectively. In addition, for the temperature-sensitive FeOx-containing structure, the resistive switching behaviors and characteristics were also investigated at room temperature and 85 degrees C. These resistive switching behaviors indicate the possible resistive switching mechanism and electrical characteristics, providing a better understanding for the temperature-sensitive FeOx-based memristors. (C) 2012 The Electrochemical Society. All rights reserved.