Browsing by Author "Chen, Wei-Ren"

Now showing 1 - 20 of 25

A study of resistive switching effects on a thin FeO(x) transition layer produced at the oxide/iron interface of TiN/SiO(2)/Fe-contented electrode structures
(2010-02-01)
Feng, Li-Wei
;
Chang, Chun-Yen
;
Chang, Yao-Feng
;
Chen, Wei-Ren
;
Wang, Shin-Yuan
Large (>10(2)) and stable resistance switching characteristics were demonstrated in TiN/SiO(2)/Fe structure due to the presence of a thin FeO(x) transition layer at the SiO(2)/Fe interface, produced spontaneously during the plasma-enhanced tetraethyl orthosilicate oxide deposition process. Addition of Pt into Fe electrode, i.e., a TiN/SiO(2)/Fe(0.73)Pt(0.27) structure, was observed to improve the data dispersion of switching parameters, associating with the decrease in Fe content inside the FeO(x) layer. Additionally, current-voltage fitting data shows that current transport mechanism is governed by Ohm's law in low voltage region and Pool-Frenkel behavior in high voltage region, consisting with FeO(x) phase transition characteristics.
A study of resistive switching effects on a thin FeOx transition layer produced at the oxide/iron interface of TiN/SiO2/Fe-contented electrode structures
(2010-02-01)
Feng, Li-Wei
;
Chang, Chun-Yen
;
Chang, Yao-Feng
;
Chen, Wei-Ren
;
Wang, Shin-Yuan
Large (>10(2)) and stable resistance switching characteristics were demonstrated in TiN/SiO2/Fe structure due to the presence of a thin FeOx transition layer at the SiO2/Fe interface, produced spontaneously during the plasma-enhanced tetraethyl orthosilicate oxide deposition process. Addition of Pt into Fe electrode, i.e., a TiN/SiO2/Fe0.73Pt0.27 structure, was observed to improve the data dispersion of switching parameters, associating with the decrease in Fe content inside the FeOx layer. Additionally, current-voltage fitting data shows that current transport mechanism is governed by Ohm's law in low voltage region and Pool-Frenkel behavior in high voltage region, consisting with FeOx phase transition characteristics.
Charge storage characteristics of Mo nanocrystal dependence on Mo oxide reduction
(2008-12-01)
Lin, Chao-Cheng
;
Chang, Ting-
;
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
;
Chang, Ting-Chang
;
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.
Enhancement of charge-storage performance in Ni-silicide nanocrystal devices by thermal annealing a Ni-Si-N thin film
(2008)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Yeh, Jui-Lung
;
Chang, Chun-Yen
;
電子工程學系及電子研究所
The stored charge characteristics of Ni-silicide nanocrystals embedded in nitride formed by annealing a Ni-Si-N thin film were studied in this paper. We used X-ray photoelectron spectroscopy, leakage current density, and X-ray diffraction to offer chemical material analysis of nanocrystals with surrounding dielectric and the crystallization of nanocrystals for different thermal annealing treatments. Transmission electron microscope analyses revealed nanocrystals embedded in the nitride layer. Nonvolatile Ni-Si nanocrystal memories with 600 degrees C annealing revealed superior electrical characteristics for charge-storage capacity and reliability compared with the memories with 300 and 500 degrees C annealing. In addition, we used energy-band diagrams to explain the significance of surrounding dielectric for reliability. (C) 2008 The Electrochemical Society.
Formation and Nonvolatile Memory Application of Ge Nanocrystals by Using Internal Competition Reaction of Si(1.33)Ge(0.67)O(2) and Si(2.67)Ge(1.33)N(2) Layers
(2009-03-01)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Hsieh, Yen-Ting
;
Chang, Chun-Yen
;
電子工程學系及電子研究所
In this study, the authors proposed a formation mechanism of Ge nanocrystals (NCs) embedded in the dielectric by using Si(1.33)Ge(0.67)O(2) and Si(2.67)Ge(1.33)N(2) films for nonvolatile memory (NVM) application. Because of internal competition reaction, this formation process reduced the thermal budget and eliminated the use of high-pressure H(2) treatment or steam process. The metal/oxide/insulator/oxide/silicon capacitor structure with NCs was also studied, and exhibited hysteresis characteristics after electrical operation. Transmission electron microscopy clearly shows the shape and density of NCs in the dielectric. In addition, the obvious memory window can be used to define "1" and "0" states at low-voltage program operation. Furthermore, good endurance and retention characteristics are exhibited for the Ge NCs embedded in SiN(x) structure. Besides, this technology is suitable for the current NVM fabrication and low-power device application.
Formation and Nonvolatile Memory Application of Ge Nanocrystals by Using Internal Competition Reaction of Si1.33Ge0.67O2 and Si2.67Ge1.33N2 Layers
(2009-03-01)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Hsieh, Yen-Ting
;
Chang, Chun-Yen
;
電子工程學系及電子研究所
In this study, the authors proposed a formation mechanism of Ge nanocrystals (NCs) embedded in the dielectric by using Si1.33Ge0.67O2 and Si2.67Ge1.33N2 films for nonvolatile memory (NVM) application. Because of internal competition reaction, this formation process reduced the thermal budget and eliminated the use of high-pressure H-2 treatment or steam process. The metal/oxide/insulator/oxide/silicon capacitor structure with NCs was also studied, and exhibited hysteresis characteristics after electrical operation. Transmission electron microscopy clearly shows the shape and density of NCs in the dielectric. In addition, the obvious memory window can be used to define "1" and "0" states at low-voltage program operation. Furthermore, good endurance and retention characteristics are exhibited for the Ge NCs embedded in SiNx structure. Besides, this technology is suitable for the current NVM fabrication and low-power device application.
Formation and nonvolatile memory characteristics of multilayer nickel-silicide NCs embedded in nitride layer
(2008-11-01)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Yeh, Jui-Lung
;
Sze, S. M.
;
Chang, Chun-Yen
The authors provided the formation and memory effects of nonvolatile multilayer nickel-silicide nanocrystal memory in this study. This proposed structure can efficiently improve the drawbacks of current floating gate and single-layer nanocrystal memories for the next-generation nonvolatile memory application. The charge trapping layer of multilayer structure was deposited by sputtering a commixed target (Ni(0.3)Si(0.7)) in the argon and nitrogen ambiance, and then used a low temperature rapid thermal annealing to form uniform nanocrystals. Transmission electron microscope images clearly show the multilayer and single-layer nanocrystal structures embedded in SiN(x). X-ray photoelectron spectroscopy and x-ray diffraction also present the chemical states and crystallization of nanocrystals under different annealing temperature treatments. The capacitor with different memory structures was also studied and exhibited hysteresis characteristics after electrical operation. In addition, the multilayer nanocrystals revealed better charge storage ability and reliability than the single-layer nanocrystals. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3006126]
Formation and nonvolatile memory effect of nickel-oxygen-silicon nanoparticles
(2007-11-26)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Yeh, Jui-Lung
;
Sze, Simon M.
;
Chang, Chun-Yen
This study reveals the formation of nickel-oxygen-silicon nanoparticles with nonvolatile memory effect by sputtering a commixed target in argon and oxygen ambiance. A transmission electron microscope clearly shows the embedded nanoparticles in the silicon oxide and the constituent was examined by x-ray photoelectron spectroscopy. The capacitor structure with embedded nickel-oxygen-silicon nanoparticles was also studied and it exhibited hysteresis characteristics after electrical operation. The memory window and retention of nickel-oxygen-silicon nanoparticles were enough to apply on nonvolatile memory. In addition, a physical mechanism was deduced to expound the role of oxygen in the formation of nickel-oxygen-silicon nanoparticles. (C) 2007 American Institute of Physics.
Formation of Ge nanocrystals using Si1.33Ge0.67O2 and Si2.67Ge1.33N2 film for nonvolatile memory application
(2007-09-03)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Hsieh, Yen-Ting
;
Sze, Simon M.
;
Chang, Chun-Yen
The authors proposed a formation mechanism of Ge nanocrystals embedded in the dielectric by using Si1.33Ge0.67O2 and Si2.67Ge1.33N2 films for nonvolatile memory application in this study. Because of internal competition reaction, this formation process reduced the thermal budget and eliminated the use of high pressure H-2 treatment or steam process. In this research, the preannealing capping oxide step is a critical process for nonvolatile memory effect. Transmission electron microscope shows the shape and density of nanocrystals in the dielectric. Moreover, the memory structure with Ge nanocrystal embedded in SiNx has better charge storage ability and data retention than Ge nanocrystal embedded in SiOx. (C) 2007 American Institute of Physics.
Formation of germanium nanocrystals by rapid thermal oxidizing SiGeO layer for nonvolatile memory application
(2007-12-15)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Tu, Chun-Hao
;
Yeh, Jui-Lung
A new method to fabricate Ge nanocrystals by rapid thermal oxidizing SiGeO layer for nonvolatile memory application was investigated in this study. The oxidation process nucleated the Ge nanocrystals embedded in the dielectric layer was clearly observed by transmission electron microscope analysis. Moreover, an over-oxidation phenomenon for the formation of GeO2 in this work was found at higher temperature oxidation according to the X-ray photoelectron spectroscopy analysis. The obvious memory window was found in the capacitance-voltage hysteresis curve, and the program efficiency of holes was superior to electrons due to the electronic affinity of GeO2 smaller than silicon substrate for a structure of Ge nanocrystals surrounded with GeO2 layer. Furthermore, the Ge nanocrystals surrounded with GeO2 layer structure has good retention time and endurance. (c) 2007 Elsevier B.V All rights reserved.
Formation of germanium nanocrystals embedded in a silicon-oxygen-nitride layer
(2007)
Tu, Chun-Hao
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Weng, Chi-Feng
;
Liu, Hsin-Chou
The formation of germanium nanocrystals embedded in silicon-oxygen-nitride with distributed charge storage elements is proposed. A large memory window was observed due to isolated Ge nanocrystals in the SiON gate stack layer. The Ge nanocrystals were nucleated after a high-temperature oxidized SiGeN layer. The Ge nanocrystals embedded in the SiON stack layer exhibited nonvolatile memory characteristics with the obvious threshold voltage shift under a bidirectional voltage sweep. Also, the manufacturing technology using the sequent high-temperature oxidation of the a-Si layer and the direct oxidation of the SiGeN layer is proposed, respectively, for the formation of a blocking oxide layer to enhance the performance of nonvolatile memory devices. The reliability characteristics, including retention time and endurance, are also advisable for the application of nonvolatile memory device. (c) 2007 The Electrochemical Society.
Formation of Mo silicide nanodot memory by rapid thermal annealing dual electron-gun evaporated Mo-Si layer
(2008)
Lin, Chao-Cheng
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Chen, Wei-Ren
;
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 stacked Ni silicide nanocrystals for nonvolatile memory application
(2007-03-12)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Lin, Po-Sun
;
Tu, Chun-Hao
The formation of stacked Ni silicide nanocrystals by using a comixed target is proposed in this letter. High resolution transmission electron microscope analysis clearly shows the stacked nanocrystals embedded in the silicon oxide. The memory window enough to define "1" and "0" states is obviously observed at low voltage programming conditions, and good data retention characteristics are exhibited for the nonvolatile memory application. A physical model is also proposed further to explain the saturation phenomenon of threshold voltage at different programming voltages with operation duration. (c) 2007 American Institute of Physics.
Fort-nation of stacked nickel-silicide nanocrystals by using a co-mixed target for nonvolatile memory application
(2007-12-15)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Tu, Chun-Hao
;
Chi, Feng-Weng
The formation of stacked nickel-silicide nanocrystals by using a co-mixed target is proposed in this paper. High resolution transmission electron microscope analysis clearly shows the stacked nanocrystals embedded in the silicon oxide after rapid thermal oxidation. The obvious memory window can be used to define "1" and "0" states at low voltage operation. In addition, the program/erase characteristics have different charge/discharge efficiency due to the effect of stacked structure. Furthermore, good endurance and retention characteristics are exhibited for nonvolatile memory application. Besides, this technology is suitable for the fabrication of current nonvolatile memory and application of low power device. (C) 2007 Elsevier B.V. All rights reserved.
Improved reliability of Mo nanocrystal memory with ammonia plasma treatment
(2009-02-09)
Lin, Chao-Cheng
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Chen, Wei-Ren
;
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
;
Chang, Ting-Chang
;
Tu, Chun-Hao
;
Chen, Wei-Ren
;
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.
Influence of hydrogen plasma treatment on charge storage characteristics in high density tungsten nanocrystal nonvolatile memory
(2011-03-31)
Chen, Shih-Cheng
;
Chang, Ting-Chang
;
Chen, Wei-Ren
;
Lo, Yuan-Chun
;
Wu, Kai-Ting
This study focuses on the influence of a hydrogen plasma treatment on electrical properties of tungsten nanocrystal nonvolatile memory. The X-ray photon emission spectra show that, after the hydrogen plasma treatment, a change in binding energy occurs such that Si(x+) and Si(y+) peaks appear at a position that is shifted about 2.3 and 3.3 eV from Si(o+) in Si 2p spectra. This indicates that Si dangling bonds are passivated to form a Si-H bond structure in the SiO(2). Furthermore, the transmission electron microscopy shows cross-sectional and plane-view for the nanocrystal microstructure after the hydrogen plasma treatment. Electrical measurement analyses show improved data retention because the hydrogen plasma treatment enhances the quality of the oxide surrounding the nanocrystals. The endurance and retention properties of the memory device are improved by about 36% and 30%, respectively. (C) 2011 Elsevier By. All rights reserved.
Multi-task Cascaded and Densely Connected Convolutional Networks Applied to Human Face Detection and Facial Expression Recognition System
(2019-01-01)
Chou, Kuan-Yu
;
Cheng, Yi-Wen
;
Chen, Wei-Ren
;
Chen, Yon-Ping
;
電控工程研究所
Face detection and recognition is an important issue and a difficult task in computer vision and human-computer interaction. Recently, with the development of deep learning, several related technologies have been proposed for face detection and facial expression recognition (FER), and the outstanding convolutional neural networks are the most common used in this field. This thesis applies the multi-task cascade convolutional neural network to face detection, and then designs the real-time FER system based on densely connected convolution network (DenseNet). The system first scales the input image to an image pyramid, and then uses the hierarchical network to determine whether a candidate window includes a human face. If a face exists, then send the candidate window to the FER system. Since DenseNet possesses the property of feature reuse, it can effectively reduce the amount of parameters and computation efforts, beneficial to develop the real-time system. In order to capture the variation of facial muscle in different expressions, this architecture adopts convolution operations with a stride 1 and tries different numbers of dense blocks. Through experiments, the proposed system can achieve real-time recognition in 30FPS and with recognition accuracy better than human eyes.
Nonvolatile memory characteristics influenced by the different crystallization of Ni-Si and Ni-N nanocrystals
(2008-02-11)
Chen, Wei-Ren
;
Chang, Ting-Chang
;
Yeh, Jui-Lung
;
Chang, Chun-Yen
;
Chen, Shih-Ching
The formation of Ni-Si and Ni-N nanocrystals by sputtering a Ni(0.3)Si(0.7) target in argon and nitrogen environment were proposed in this paper. A transmission electron microscope analysis shows the nanocrystals embedded in the nitride layer. X-ray photoelectron spectroscopy and x-ray diffraction also offer the chemical material analysis of nanocrystals with surrounding dielectric and the crystallization of nanocrystals for different thermal annealing treatments. Nonvolatile Ni-Si nanocrystal memories reveal superior electrical characteristics for charge storage capacity and reliability due to the improvement of thermal annealing treatment. In addition, we used energy band diagrams to explain the significance of surrounding dielectric for reliability. (c) 2008 American Institute of Physics.