Browsing by Author "Gan, Der-Shin"

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Bipolar Resistive RAM Characteristics Induced by Nickel Incorporated Into Silicon Oxide Dielectrics for IC Applications
(2012-12-01)
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
;
Chang, Ting-Chang
;
Syu, Yong-En
;
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
;
Tsai, Tsung-Ming
;
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.
Effect of Electrode Material on Resistive Switching Characteristics in TaON Nonvolatile Memory Devices
(2013-01-01)
Chen, Min-Chen
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Chang, Ting-Chang
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Chiu, Yi-Chieh
;
Chen, Shih-Cheng
;
Huang, Sheng-Yao
The devices composed of Pt/TaON/TiN reveal bipolar switching behavior that shows excellent resistance ratio of 10(2) with operations over 100 DC cycles. The formation/disruption of conducting filaments by oxygen anions migration near/at the TiN electrode was applied to explain the switching behavior. In comparison with Pt/TaON/TiN device, the Cu/TaON/TiN device exhibits reversed bipolar resistive switching characteristic. The switching mechanism of Cu/TaON/TiN device is regarded as the Cu redox reaction and migration in the TaON film. Furthermore, the setting voltage of the Cu/TaON/TiN device is lower than that of the Pt/TaON/TiN device due to the confined conduction path by Cu filaments.
Endurance Improvement Technology With Nitrogen Implanted in the Interface of WSiOx Resistance Switching Device
(2013-07-01)
Syu, Yong-En
;
Zhang, Rui
;
Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
Incorporation of nitrogen as an oxygen-confining layer in the resistance switching reaction region is investigated to improve the reliability of resistance random access memory (RRAM). The switching mechanism can be attributed to the formation and rupture of conduction filaments. A compatible WSiON (around 5 nm) layer is introduced at the interface of tungsten silicon oxide (WSiOx) and TiN electrode to prevent the randomly diffusing oxygen ions surpassing the storage region of the WSiON layer. The double-layer WSiOx/WSiON memory structure would enhance the endurance over 100 times so as to better confirm the WSiOx RRAM application of nonvolatile memory.
Enhancement of the stability of resistive switching characteristics by conduction path reconstruction
(2013-07-22)
Huang, Jheng-Jie
;
Chang, Ting-Chang
;
Yu, Chih-Cheng
;
Huang, Hui-Chun
;
Chen, Yu-Ting
In this study, a Pt/BiFeO3/TiN device was fabricated and the resistance switching characteristics were investigated. After the first forming process, the conduction path was formed and exhibited unstable bipolar switching characteristics. Subsequently, the original conduction path was destroyed thoroughly by high negative bias. By reconstructing the conduction path after a second forming process (re-forming process), the device exhibits stable bipolar switching characteristics. Transmission electron microscopy analysis indicates that the stability of switching behavior was enhanced because of the joule heating effect, and is an easy way to improve the resistance switching characteristics. (C) 2013 AIP Publishing LLC.
Formation and composition of titanium oxinitride nanocrystals synthesized via nitridizing titanium oxide for nonvolatile memory applications
(2011-09-01)
Feng, Li-Wei
;
Chang, Chun-Yen
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Wang, Pai-Syuan
Formation and composition analyses of titanium oxinitride nanocrystals (NCs) fabricated via treating a magnetron co-sputtered thin film of titanium and silicon dioxide with a rapid thermal annealing in nitrogen ambient were demonstrated for nonvolatile memory applications. Phase separation characteristics with different annealing conditions were examined by transmission electron microscopy and chemical bonding characteristics were confirmed by X-ray photon emission spectra. It was observed that a blanket layer composed mainly of titanium oxide was still present as annealing temperature was increased to 700 degrees C, associated with the thermodynamically stable phase of titanium oxide. Furthermore, a higher thermal treatment of 900 degrees C induced formation of a well-separated NC structure and caused simultaneously partial nitridation of the titanium oxide, thereby forming titanium oxinitride NCs. A significant capacitance-voltage hysteresis in threshold voltage shift at 1 V was easily achieved under a small sweeping voltage range of + 2 V/-2 V, and a memory window retention of 2.2 V was obtained after 10(7) s by extrapolation under a 1 s initial-program/erase condition of +5 V/-5 V, respectively. (C) 2011 Elsevier B.V. All rights reserved.
Hopping Effect of Hydrogen-Doped Silicon Oxide Insert RRAM by Supercritical CO2 Fluid Treatment
(2013-05-01)
Chang, Kuan-Chang
;
Pan, Chih-Hung
;
Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Zhang, Rui
In this letter, we introduced hydrogen ions into titanium metal doped into SiO2 thin film as the insulator of resistive random access memory (RRAM) by supercritical carbon dioxide (SCCO)(2) fluid treatment. After treatment, low resistance state split in to two states, we find the insert RRAM, which means it has an operating polarity opposite from normal RRAM. The difference of the insert RRAM is owing to the resistive switching dominated by hydrogen ions, dissociated from OH bond, which was not by oxygen ions as usual. The current conduction mechanism of insert RRAM was hopping conduction due to the metal titanium reduction reaction through SCCO2.
Improvement in the bias stability of amorphous InGaZnO TFTs using an Al2O3 passivation layer
(2013-09-01)
Huang, Sheng-Yao
;
Chang, Ting-Chang
;
Chen, Min-Chen
;
Chen, Te-Chih
;
Jian, Fu-Yen
This work presents the light-color-dependent negative bias stress (NBIS) effect on amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) with Al2O3 passivation layer. The colors of incident photon are varied from red to blue, that incident photon energies are all lower than the optical band gap of IGZO (3.2 eV). The experimental results show that the Al2O3 passivated devices present stable electrical behaviors under different incident lights (Delta V-T<0.1 V of dark and red, Delta V-T<1 V of green, and Delta V-T<4 V of blue), whereas the unpassivation devices exhibit observable negative shifts during NBIS (Delta V-T<1 V of dark and red, Delta V-T>8 V of green, and Delta V-T>15 V of blue). The degradation mechanism of the negative bias stress under illumination of a-IGZO TFTs is dominated by the photo-generated hole trapping at the gate insulator and/or interface between insulator and channel. In this result, the Al2O3 passivation layer can effectively passivate the defect in the a-IGZO film, reducing electron hole pair generated during the illumination processed. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.
Improvement of the performance of ZnO TFTs by low-temperature supercritical fluid technology treatment
(2009-12-25)
Chen, Min-Chen
;
Chang, Ting-Chang
;
Huang, Sheng-Yao
;
Chang, Kuan-Chang
;
Huang, Hui-Chun
in this paper, the supercritical CO(2) (SCCO(2)) fluid technology is successfully applied to improve the electrical characteristics of sputtered ZnO TFTs at low temperature (150 degrees C). After the treatment of SCCO(2) fluids mixed with water, the ZnO TFT exhibited superior transfer characteristics and lower threshold voltage. According to X-ray photoelectron spectroscopy (XPS) analyses, the improvements were attributed to the increase of binding energies of Zn-O bonds, hydrogen-related donors and the reduction of traps at the grain boundaries in ZnO thin films. In addition, the crystalline quality and microstructure of ZnO thin films were also investigated by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The transmittance of the ZnO film was measured by an N&K analyzer 1280 (N&K Technology, Inc.), which is a new type of thin-film measurement system. (C) 2009 Elsevier B.V. All rights reserved.
Influence of molybdenum doping on the switching characteristic in silicon oxide-based resistive switching memory
(2013-01-28)
Chen, Yu-Ting
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Chang, Ting-Chang
;
Huang, Jheng-Jie
;
Tseng, Hsueh-Chih
;
Yang, Po-Chun
This report compares Mo-doped and undoped SiO2 thin films of a similar thickness as well as MoOx. The Mo-doped SiO2 film exhibited switching behavior after the forming process, unlike the undoped SiO2 film. Through material analyses, a self-assembled layer is observed in the Mo-doped SiO2 film. Due to the formation of this layer, the thickness required to be broken down is effectively reduced. Subsequently, the occurrence of the switching behavior in the thinner SiO2 film further confirmed the supposition. A comparison of the two switching behaviors shows that SiO2 dominates the switching characteristic of the Mo-doped SiO2. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790277]
Influence of Oxygen Partial Pressure on Resistance Random Access Memory Characteristics of Indium Gallium Zinc Oxide
(2011)
Chen, Min-Chen
;
Chang, Ting-Chang
;
Huang, Sheng-Yao
;
Chang, Guan-Chang
;
Chen, Shih-Cheng
This paper investigates the effect of oxygen concentrations of InGaZnO films on the resistive switching characteristics of a Pt/InGaZnO (IGZO)/TiN structure. The IGZO films were prepared by an RF magnetron sputtering system at various oxygen partial pressures at room temperature. The memory devices reveal a reversible unipolar switching behavior. In addition, the high-resistance state current was found to be strongly dependent on oxygen concentration. X-ray photoelectron spectroscopy analyses attributed this phenomenon to the non-lattice oxygen concentration in the IGZO thin films, rather than the change in crystalline constituent. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.007112esl] 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
;
Chang, Ting-Chang
;
Wu, Hsing-Hua
;
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.
Low temperature synthesis and electrical characterization of germanium doped Ti-based nanocrystals for nonvolatile memory
(2011-11-30)
Feng, Li-Wei
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Chang, Chun-Yen
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Chang, Ting-Chang
;
Tu, Chun-Hao
;
Wang, Pai-Syuan
Chemical and electrical characteristics of Ti-based nanocrystals containing germanium, fabricated by annealing the co-sputtered thin film with titanium silicide and germanium targets, were demonstrated for low temperature applications of nonvolatile memory. Formation and composition characteristics of nanocrystals (NCs) at various annealing temperatures were examined by transmission electron microscopy and X-ray photon-emission spectroscopy, respectively. It was observed that the addition of germanium (Ge) significantly reduces the proposed thermal budget necessary for Ti-based NC formation due to the rise of morphological instability and agglomeration properties during annealing. NC structures formed after annealing at 500 degrees C, and separated well at 600 degrees C annealing. However, it was also observed that significant thermal desorption of Ge atoms occurs at 600 degrees C due to the sublimation of formatted GeO phase and results in a serious decrease of memory window. Therefore, an approach to effectively restrain Ge thermal desorption is proposed by encapsulating the Ti-based trapping layer with a thick silicon oxide layer before 600 degrees C annealing. The electrical characteristics of data retention in the sample with the 600 degrees C annealing exhibited better performance than the 500 C-annealed sample, a result associated with the better separation and better crystallization of the NC structures. (C) 2011 Elsevier B.V. All rights reserved.
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
;
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.
Reducing operation current of Ni-doped silicon oxide resistance random access memory by supercritical CO(2) fluid treatment
(2011-12-26)
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Chang, Ting-Chang
;
Syu, Yong-En
;
Wang, Chia-C.
In the study, we reduced the operation current of resistance random access memory (RRAM) by supercritical CO(2) (SCCO(2)) fluids treatment. The power consumption and joule heating degradation of RRAM device can be improved greatly by SCCO(2) treatment. The defect of nickel-doped silicon oxide (Ni:SiO(x)) was passivated effectively by the supercritical fluid technology. The current conduction of high resistant state in post-treated Ni:SiO(x) film was transferred to Schottky emission from Frenkel-Pool due to the passivation effect. Additionally, we can demonstrate the passivation mechanism of SCCO(2) for Ni:SiO(x) by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3671991]
Reducing operation current of Ni-doped silicon oxide resistance random access memory by supercritical CO2 fluid treatment
(2011-12-26)
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Chang, Ting-Chang
;
Syu, Yong-En
;
Wang, Chia-C.
In the study, we reduced the operation current of resistance random access memory (RRAM) by supercritical CO2 (SCCO2) fluids treatment. The power consumption and joule heating degradation of RRAM device can be improved greatly by SCCO2 treatment. The defect of nickel-doped silicon oxide (Ni:SiOx) was passivated effectively by the supercritical fluid technology. The current conduction of high resistant state in post-treated Ni:SiOx film was transferred to Schottky emission from Frenkel-Pool due to the passivation effect. Additionally, we can demonstrate the passivation mechanism of SCCO2 for Ni:SiOx by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3671991]
Resistive switching characteristics of Sm(2)O(3) thin films for nonvolatile memory applications
(2011-09-01)
Huang, Sheng-Yao
;
Chang, Ting-Chang
;
Chen, Min-Chen
;
Chen, Shih-Ching
;
Lo, Hung-Ping
This study investigates a sputtered Sm(2)O(3) thin film to apply into a resistive random access memory device. The proposed device exhibits a stable resistance ratio of about 2.5 orders after 10(4) cycling bias pulses and no degradation for retention characteristics monitored after an endurance test at 85 degrees C. The conduction mechanisms for low and high resistance states are dominated by ohmic behavior and trapcontrolled space charge limited current, respectively. The resistance switching is ascribed to the formation/rupture of conductive filaments. (C) 2011 Elsevier Ltd. All rights reserved.
Resistive switching characteristics of Sm2O3 thin films for nonvolatile memory applications
(2011-09-01)
Huang, Sheng-Yao
;
Chang, Ting-Chang
;
Chen, Min-Chen
;
Chen, Shih-Ching
;
Lo, Hung-Ping
This study investigates a sputtered Sm2O3 thin film to apply into a resistive random access memory device. The proposed device exhibits a stable resistance ratio of about 2.5 orders after 10(4) cycling bias pulses and no degradation for retention characteristics monitored after an endurance test at 85 degrees C. The conduction mechanisms for low and high resistance states are dominated by ohmic behavior and trapcontrolled space charge limited current, respectively. The resistance switching is ascribed to the formation/rupture of conductive filaments. (C) 2011 Elsevier Ltd. All rights reserved.
Resistive switching characteristics of ytterbium oxide thin film for nonvolatile memory application
(2011-12-30)
Tseng, Hsueh-Chih
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Chang, Ting-Chang
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Huang, Jheng-Jie
;
Chen, Yu-Ting
;
Yang, Po-Chun
This paper studies the effects of both the positive and negative forming processes on the resistive switching characteristics of a Pt/Yb(2)O(3)/TiN RRAM device. The polarity of the forming process can determine the transition mechanism, either bipolar or unipolar. Bipolar behavior exists after the positive forming process, while unipolar behavior exists after the negative forming process. Furthermore, the bipolar switching characteristics of the Pt/Yb(2)O(3)/TiN device can be affected by using a reverse polarity forming treatment, which not only reduces the set and reset voltage, but also improves the on/off ratio. Crown Copyright (C) 2011 Published by Elsevier B. V. All rights reserved.
Space electric field concentrated effect for Zr:SiO2 RRAM devices using porous SiO2 buffer layer
(2013-12-11)
Chang, Kuan-
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Huang, Jen-wei
;
Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Chen, Kai-Huang
To improve the operation current lowing of the Zr:SiO2 RRAM devices, a space electric field concentrated effect established by the porous SiO2 buffer layer was investigated and found in this study. The resistive switching properties of the low-resistance state (LRS) and high-resistance state (HRS) in resistive random access memory (RRAM) devices for the single-layer Zr:SiO2 and bilayer Zr:SiO2/porous SiO2 thin films were analyzed and discussed. In addition, the original space charge limited current (SCLC) conduction mechanism in LRS and HRS of the RRAM devices using bilayer Zr:SiO2/porous SiO2 thin films was found. Finally, a space electric field concentrated effect in the bilayer Zr:SiO2/porous SiO2 RRAM devices was also explained and verified by the COMSOL Multiphysics simulation model.