Browsing by Author "Lin, Chao-Cheng"

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A Study of the Relationship Between Endurance and Retention Reliability for a HfOx-Based Resistive Switching Memory
(2020-09-01)
Chung, Wei-Min
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Chang, Yao-Feng
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Hsu, Yu-Lin
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Chen, Y. -C. Daphne
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Lin, Chao-Cheng
This study determines the relationship between retention and endurance reliability for a HfOx-based resistive random access memory (ReRAM). A TiN (15 nm) / HfOx (6 nm) / Ti (10 nm) / TiN (40 nm) stacked structure is fabricated and tested to verify its basic characteristics and reliability. The high resistance states (HRS) retention behavior is characterized and is found to degrade over 100x on the endured bits because there is a sequential high temperature procedure. The degradation is reduced slightly to a similar to 30x drop for the endured devices with one single refresh cycle. During the endurance and retention test procedures, the HRS resistance decreases because neutral oxygen vacancy filaments grow and this cannot be reversed. The I-V characteristics for endured devices are also determined. The results show that isothermal treatment causes a gradual SET and RESET process with multiple feasible states. The thermally induced filament degradation model (isolated filament vs. continuous filament) is verified by the relationship between retention and endurance reliability. Design guidance is recommended for an improvement in ReRAM reliability.
Analytical Modeling of Read-Induced SET-State Conductance Change in a Hafnium-Oxide Resistive Switching Device
(2020-01-01)
Su, Po-Cheng
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Jiang, Cheng-Min
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Chen, Yu-Jia
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Wang, Chih-Chieh
;
Li, Kai-Shin
A SET-state conductance change in a hafnium-oxide resistive switching memory cell due to repeated read events is investigated. We characterize a read-induced conductance change at different read voltages and SET-state conductance levels. Our result shows that the read-induced conductance degradation exhibits a two-stage evolution with the read pulse number. A SET-state conductance decreases slightly in the first stage and then follows inverse power-law dependence on the read number in the second stage. The power factor is an exponential function of a read voltage without regard to the SET-state conductance level, and the read pulse number at the transition of the two stages is related to a read voltage and conductance level. An analytical model to describe the two-stage conductance evolution is proposed. The parameters in the model are extracted from measurement data. Our model is verified by good agreement between the modeled and measured results in a wide range of read pulse number, read voltage, and SET-state conductance level.
Charge storage characteristics of high density Mo nanocrystal embedded in silicon oxide and silicon nitride
(2010-02-24)
Lin, Chao-Cheng
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chen, Shih-Ching
;
Hu, Chih-Wei
We investigated the formation and charge storage characteristics of Mo nanocrystals in silicon oxide and in silicon nitride by rapid thermal annealing of oxygen- and nitrogen-incorporated Mo and Si mixed layers. A high density of Mo nanocrystal (6 x 10(12) cm(-2)) was formed in the nitrogen-incorporated layer. Electrical analyses indicated that the memory window of the Mo nanocrystal embedded in the nitride is larger than that in the oxide. A reliability test showed that the Mo nanocrystal in the nitride has better reliability than the Mo nanocrystal in the oxide, which was explained by an electrical field simulation.
Charge storage characteristics of Mo nanocrystal dependence on Mo oxide reduction
(2008-12-01)
Lin, Chao-Cheng
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Chang, Ting-
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Tu, Chun-Hao
;
Chen, Wei-Ren
;
Hu, Chih-Wei
An oxygen incorporated Mo silicide was explored to form the Mo nanocrystals after rapid thermal annealing. Transmission electron microscopy showed the nanocrystals embedded in SiO(x). Charge storage characteristics of Mo nanocrystals influenced by the Mo oxide and the surrounding oxide were investigated through x-ray photoelectron spectroscopy and the electrical measurement. X-ray photoelectron spectra analyses revealed the redox reaction in the oxygen incorporated Mo silicide layer after rapid thermal annealing. The memory window and retention were improved due to reduction in Mo oxide.
Charge Storage Characteristics of Mo Nanocrystal Memory Influenced by Ammonia Plasma Treatment
(2009)
Lin, Chao-Cheng
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Chang, Ting-Chang
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Tu, Chun-Hao
;
Chen, Wei-Ren
;
Hu, Chih-Wei
Mo nanocrystal memory was fabricated through annealing the oxygen-incorporated Mo and Si layers. We then investigated the influence an of ammonia plasma treatment on the nonvolatile memory characteristics of a charge storage layer composed of Mo nanocrystal memory embedded in SiO(x). Transmission electron microscopy revealed the nanostructure of the charge storage layer, and X-ray photoelectron spectra analyses revealed that nitrogen was incorporated into the charge storage layer. Electric analyses indicated that the memory window reduced, and both retention and endurance improved after the treatment. The reduction in the memory window was attributed to the decrease in charge trapping centers in the surrounding oxide after the treatment. The improvement of retention was interpreted in terms of the nitrogen passivation of traps in the oxide around the Mo nanocrystals. The robust endurance characteristic was attributed to the improvement of the quality of the surrounding oxide by nitrogen passivation.
Cobalt nanodots formed by annealing the CoSiO layer for the application of the nonvolatile memory
(2009-03-09)
Hu, Chih-Wei
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Chang, Ting-Chang
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Tu, Chun-Hao
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Shueh, Pei-Kun
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Lin, Chao-Cheng
Co nanodot memory devices formed by oxidation processes were studied. Transmission electron microscopy and x-ray photoelectron spectroscopy analyses showed that overoxidation of the cobalt and silicon degraded the charge-storage ability seriously. However, a precapped oxide can mildly oxidize the CoSi(2) film to protect the overoxidation to occur. In addition, an oxygen-incorporated CoSi(2) film is proposed to improve the oxidation process further. Through incorporating the limited oxygen during sputtering process, the Co nanodot memory device obtains a larger memory window. Also, the reliability characteristic of the Co nanodot memory device formed by annealing the oxygen-incorporated CoSi(2) film has been demonstrated.
Effect of Hydrogen Dilution on the Intrinsic a-Si:H Film of the Heterojunction Silicon-Based Solar Cell
(2011)
Hsiao, Jui-Chung
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Chen, Chien-Hsun
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Lin, Chao-Cheng
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Wu, Der-Ching
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Yu, Peichen
In this work, effects of a hydrogen dilution ratio on the intrinsic amorphous hydrogenated silicon (i-a-Si:H) film of heterojunction silicon-based (HJS) solar cells were systematically studied. Long lifetime samples were obtained for R <= 5, indicating a good a-Si:H/c-Si interface. The dark conductivity was drastically decreased for R >= 2, indicating a good film quality. Consequently, an optimized power conversion efficiency of the HJS solar cells was obtained at a moderate R between 2 and 5. In contrast to the previous emphasis on long lifetime, the results indicate that both the interface and film qualities are correlated to the hydrogen dilution, which are important to achieve high-efficiency HJS solar cells. We show that the most optimized HJS solar cell exhibits a marked efficiency of 17.27%. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3607981] All rights reserved.
Effect of Top Electrode Material on Resistive Switching Characteristics in MnO2 Nonvolatile Memory Devices
(2011)
Tsai, Yu-Ting
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Chang, Ting-Chang
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Lin, Chao-Cheng
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Chiang, Lan-Shin
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Chen, Shih-Cheng
The influence of top electrode material on the resistive switching properties of MnO2-based memory film using Pt as a bottom electrode was investigated in this study. In comparison with Pt/MnO2/Pt and Al/ MnO2/Pt devices, the Ti/ MnO2/Pt device exhibits resistive switching current-voltage (I-V) curve, which can be traced and reproduced more than 10(5) times only showing a little decrease of resistance ratio between high and low resistance states. Furthermore, transmission electron microscopy analyses are used to confirm the crystalline structure of MnO2 on Pt bottom electrode. Secondary ion mass spectrometry reveals a change of oxygen distribution in MnO2 thin film due to material characteristic of variant top electrodes. We suggest that the interface between MnO2 and electrodes play an important role on the resistive switching behaviors.
Enhancement of NiSi-Based Nanocrystal Formation by Incorporating Ge Elements for Nonvolatile Memory Devices
(2009)
Hu, Chih-Wei
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chiang, Cheng-Neng
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Lin, Chao-Cheng
In this work, a NiSiGe mixed film was deposited by the cosputtering approach. The rapidly thermal treatment condition was executed at 600 degrees C for 30 s in nitrogen ambient to form the nanocrystal structure. From the results of the transmission electron microscopy, the annealed NiSiGe film reveals a larger nanocrystal size and density distribution than pure NiSi. X-ray photoelectron spectroscopy analyses were used to confirm that the Ge elements provide the additional nucleation centers and enhance the nanocrystal formation during the thermal process. Raman spectroscopy and an energy-dispersive spectrometer also exhibit the compositions of nanocrystals including Ni, Si, and Ge elements. With the better formation process, a remarkable improvement of memory effect is observed by comparing with the NiSi and NiSiGe nanocrystal memory devices. Also, the NiSiGe nanocrystal device shows a better retention characteristic due to the lower quantum confinement effect.
Formation and composition of titanium oxinitride nanocrystals synthesized via nitridizing titanium oxide for nonvolatile memory applications
(2011-09-01)
Feng, Li-Wei
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Chang, Chun-Yen
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Chang, Ting-Chang
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Tu, Chun-Hao
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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.
Formation of Mo silicide nanodot memory by rapid thermal annealing dual electron-gun evaporated Mo-Si layer
(2008)
Lin, Chao-Cheng
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chen, Wei-Ren
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Hu, Chih-Wei
In this study, distributed charge trapping centers molybdenum silicide nanodots, are demonstrated. The Mo silicide nanodots were formed in the rapid thermal annealed mixed Mo-Si layer deposited by a dual electron gun system. A significant memory effect is observed through the electrical measurements, which is attributed to the formation of Mo silicide nanodots. In addition, the memory window is large enough to be identified as logic level "0" and "1" for the application on nonvolatile memory. The manufacture processes are simple and compatible with the conventional semiconductor manufacturing processes. (C) 2008 The Electrochemical Society.
Formation of the distributed NiSiGe nanocrystals nonvolatile memory formed by rapidly annealing in N(2) and O(2) ambient
(2010-10-01)
Hu, Chih-Wei
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chiang, Cheng-Neng
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Lin, Chao-Cheng
In this work, electrical characteristics of the Ge-incorporated Nickel silicide (NiSiGe) nanocrystals memory device formed by the rapidly thermal annealing in N(2) and O(2) ambient have been studied. The trapping layer was deposited by co-sputtering the NiSi(2) and Ge, simultaneously. Transmission electron microscope results indicate that the NiSiGe nanocrystals were formed obviously in both the samples. The memory devices show obvious charge-storage ability under capacitance-voltage measurement. However, it is found that the NiSiGe nanocrystals device formed by annealing in N(2) ambient has smaller memory window and better retention characteristics than in O(2) ambient. Then, related material analyses were used to confirm that the oxidized Ge elements affect the charge-storage sites and the electrical performance of the NCs memory. (C) 2010 Elsevier B.V. All rights reserved.
Formation of the distributed NiSiGe nanocrystals nonvolatile memory formed by rapidly annealing in N-2 and O-2 ambient
(2010-10-01)
Hu, Chih-Wei
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chiang, Cheng-Neng
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Lin, Chao-Cheng
In this work, electrical characteristics of the Ge-incorporated Nickel silicide (NiSiGe) nanocrystals memory device formed by the rapidly thermal annealing in N-2 and O-2 ambient have been studied. The trapping layer was deposited by co-sputtering the NiSi2 and Ge, simultaneously. Transmission electron microscope results indicate that the NiSiGe nanocrystals were formed obviously in both the samples. The memory devices show obvious charge-storage ability under capacitance-voltage measurement. However, it is found that the NiSiGe nanocrystals device formed by annealing in N-2 ambient has smaller memory window and better retention characteristics than in O-2 ambient. Then, related material analyses were used to confirm that the oxidized Ge elements affect the charge-storage sites and the electrical performance of the NCs memory. (C) 2010 Elsevier B.V. All rights reserved.
High Density Ni Nanocrystals Formed by Coevaporating Ni and SiO(2) Pellets for the Nonvolatile Memory Device Application
(2010-01-01)
Hu, Chih-Wei
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Chang, Ting-Chang
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Tu, Chun-Hao
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Huang, Yu-Hao
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Lin, Chao-Cheng
We propose a method to fabricate a Ni nanocrystal structure by simultaneously coevaporating Ni and SiO(2) pellets. An 800 degrees C rapid thermal annealing was used to enhance the Ni nanocrystals to aggregate. Transmission electron microscopy indicates that the formed Ni nanocrystals show a high density distribution of about 4.5x10(12) cm(-2). Then, the memory device using the Ni nanocrystals as charge-trapping centers was fabricated. The Ni nanocrystal memory device has an obvious memory window under capacitance-voltage measurement. X-ray photoelectron spectroscopy confirms the memory effect results from the Ni nanocrystals embedded in the SiO(2) dielectric layer. Moreover, related reliability characteristics have been extracted.
High Density Ni Nanocrystals Formed by Coevaporating Ni and SiO2 Pellets for the Nonvolatile Memory Device Application
(2010-01-01)
Hu, Chih-Wei
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Huang, Yu-Hao
;
Lin, Chao-Cheng
We propose a method to fabricate a Ni nanocrystal structure by simultaneously coevaporating Ni and SiO2 pellets. An 800 degrees C rapid thermal annealing was used to enhance the Ni nanocrystals to aggregate. Transmission electron microscopy indicates that the formed Ni nanocrystals show a high density distribution of about 4.5x10(12) cm(-2). Then, the memory device using the Ni nanocrystals as charge-trapping centers was fabricated. The Ni nanocrystal memory device has an obvious memory window under capacitance-voltage measurement. X-ray photoelectron spectroscopy confirms the memory effect results from the Ni nanocrystals embedded in the SiO2 dielectric layer. Moreover, related reliability characteristics have been extracted.
Highly textured ZnO:B films grown by low pressure chemical vapor deposition for efficiency enhancement of heterojunction silicon-based solar cells
(2013-09-01)
Hsiao, Jui-Chung
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Chen, Chien-Hsun
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Yang, Hung-Jen
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Wu, Chien-Liang
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Fan, Chia-Ming
This paper demonstrates the growth of highly-textured boron-doped ZnO (ZnO:B) film by using low-pressure chemical-vapor-deposition (LPCVD) for efficient light harvesting and carrier collection in heterojunction silicon-based (HJS) solar cells. The optical and electrical characteristics have been optimized versus the substrate temperature and B2H6 flow rate for tradeoffs among the sheet resistance, free-carrier absorption, and optical transmission of blue/green wavelengths. A HJS solar cell with a 1.6-mu m-thick ZnO:B film achieves a high power conversion efficiency of 16.30% and fill factor of 78.05%, compared to 15.64% and 72.17%, respectively, from a counterpart with a conventional 80-nm-thick indium tin oxide layer. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Improved reliability of Mo nanocrystal memory with ammonia plasma treatment
(2009-02-09)
Lin, Chao-Cheng
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chen, Wei-Ren
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Hu, Chih-Wei
We investigated ammonia plasma treatment influence on the nonvolatile memory characteristics of the charge storage layer composed of Mo nanocrystals embedded in nonstoichiometry oxide (SiO(x)). X-ray photoelectron spectra analyses revealed that nitrogen was incorporated into the charge storage layer. Electric analyses indicated that the memory window was reduced and the retention and the endurance improved after the treatment. The reduction in the memory window and the improvement in retention were interpreted in terms of the nitrogen passivation of traps in the oxide around Mo nanocrystals. The robust endurance characteristic was attributed the improvement of the quality of the surrounding oxide by nitrogen passivation.
Improvement of Charge-Storage Characteristics of Mo Nanocrystal Memory by Double-Layer Structure
(2009)
Lin, Chao-Cheng
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Chang, Ting-Chang
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Tu, Chun-Hao
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Chen, Wei-Ren
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Feng, Li-Wen
An oxygen-incorporated Mo silicide layer was explored to form the Mo nanocrystals after rapid thermal annealing. Transmission electron microscopy showed the nanocrystals embedded in SiO(x). Charge-storage characteristics of Mo nanocrystals influenced by Mo oxide and its surrounding oxide were investigated through X-ray photoelectron spectroscopy and electrical measurement. X-ray photoelectron spectral analyses revealed a redox reaction in the oxygen-incorporated Mo silicide layer after rapid thermal annealing at a critical temperature. The memory window and retention were improved because of the reduction of Mo oxide. Furthermore, the double-layer nanocrystal structure was fabricated through the annealed stacked oxygen incorporated Mo silicide layer. A larger memory window and long retention were found for the double-layer nanocrystal structure. We used an energy band diagram to explain the difference in retention characteristics between single- and double-layer structures.
Improvement of resistance switching characteristics in a thin FeO(x) transition layer of TiN/SiO(2)/FeO(x)/FePt structure by rapid annealing
(2010-05-31)
Feng, Li-Wei
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Chang, Chun-Yen
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Chang, Yao-Feng
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Chang, Ting-Chang
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Wang, Shin-Yuan
In this paper, the influence of a 600 degrees C rapid thermal annealing for 60 s on the improvements of resistance switching behaviors in a TiN/SiO(2)/FeO(x)/FePt structure is reported. It is found that besides the distinct reduction in memory switching parameters in forming voltage, set/reset voltages, and their dispersions, the resistance ratio of high-resistance state to low-resistance state is also enlarged after annealing. The effects of annealing on improving the resistance switching properties are discussed by x-ray diffraction and x-ray photon-emission spectra depth profile results. Additionally, good retention characteristics are exhibited in the annealed TiN/SiO(2)/FeO(x)/FePt resistance switching memory. (C) 2010 American Institute of Physics. [doi:10.1063/1.3428777]
Improvement of resistance switching characteristics in a thin FeOx transition layer of TiN/SiO2/FeOx/FePt structure by rapid annealing
(2010-05-31)
Feng, Li-Wei
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Chang, Chun-Yen
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Chang, Yao-Feng
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Chang, Ting-Chang
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Wang, Shin-Yuan
In this paper, the influence of a 600 degrees C rapid thermal annealing for 60 s on the improvements of resistance switching behaviors in a TiN/SiO2/FeOx/FePt structure is reported. It is found that besides the distinct reduction in memory switching parameters in forming voltage, set/reset voltages, and their dispersions, the resistance ratio of high-resistance state to low-resistance state is also enlarged after annealing. The effects of annealing on improving the resistance switching properties are discussed by x-ray diffraction and x-ray photon-emission spectra depth profile results. Additionally, good retention characteristics are exhibited in the annealed TiN/SiO2/FeOx/FePt resistance switching memory. (C) 2010 American Institute of Physics. [doi:10.1063/1.3428777]