Browsing by Author "Lin, Meng-Han"

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Characteristics of SrTiO(3) Insulated Layer in SBT Ferroelectric Thin Films
(2009-01-01)
Chou, Hsiu-Yu
;
Lee, En-Ko
;
Lin, Meng-Han
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Low temperature processing of SBT thin films with SrTiO(3) (STO) seeded layer deposited onto Ir/SiO(2)/Si (MIM structure) and CeO(2)/Si (MFIS structure) substrate using MOD method was investigated. The Sr(0.8)Bi(2.6)Ta(2)O(9+x) (SBT) thin films with a STO seeded layer on MIM structure showed prefer (115) orientation, well crystalline and lower crystal temperature than those without STO seeded layer. The SBT thin films with STO seeded layer on MFIS structure also showed prefer (115), (006) orientation and well crystalline SBT phase annealed at 700 degrees C. The seeded layer, STO, effectively protected the evaporation of Bi through the Pt top electrode and diffusion of Bi into the Ir bottom electrode on MIM structure. It also can improve the crystallization of SBT phase, grain growth and lower crystallized temperature of SBT thin film. The memory window and leakage current densities of SBT thin films with STO seeded layers are improved significantly in comparison with those films without the STO seeded layer. In the MIM structure, the SBT thin film with STO seeded layer can decrease the leakage current density to 10-9 A/cm(2) at 100 kV/cm. In the MFIS structure, the SBT thin film with STO seeded layer also can improve the memory window and lead to lower leakage current at low voltage.
Characteristics of SrTiO3 Insulated Layer in SBT Ferroelectric Thin Films
(2009-01-01)
Chou, Hsiu-Yu
;
Lee, En-Ko
;
Lin, Meng-Han
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Low temperature processing of SBT thin films with SrTiO3 (STO) seeded layer deposited onto Ir/SiO2/Si (MIM structure) and CeO2/Si (MFIS structure) substrate using MOD method was investigated. The Sr0.8Bi2.6Ta2O9+x (SBT) thin films with a STO seeded layer on MIM structure showed prefer (115) orientation, well crystalline and lower crystal temperature than those without STO seeded layer. The SBT thin films with STO seeded layer on MFIS structure also showed prefer (115), (006) orientation and well crystalline SBT phase annealed at 700 degrees C. The seeded layer, STO, effectively protected the evaporation of Bi through the Pt top electrode and diffusion of Bi into the Ir bottom electrode on MIM structure. It also can improve the crystallization of SBT phase, grain growth and lower crystallized temperature of SBT thin film. The memory window and leakage current densities of SBT thin films with STO seeded layers are improved significantly in comparison with those films without the STO seeded layer. In the MIM structure, the SBT thin film with STO seeded layer can decrease the leakage current density to 10-9 A/cm(2) at 100 kV/cm. In the MFIS structure, the SBT thin film with STO seeded layer also can improve the memory window and lead to lower leakage current at low voltage.
Effects of Vanadium Doping on Resistive Switching Characteristics and Mechanisms of SrZrO(3)-Based Memory Films
(2010-08-01)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The effects of vanadium doping on resistive switching (RS) characteristics and mechanisms of RF-sputtered SrZrO(3) (SZO)-based thin films are investigated in this paper. The physical and electrical properties of SZO-based thin films are modulated by vanadium doping due to the Zr(4+) ion replaced by V(5+), further affecting the RS parameters of SZO-based thin films. The conduction mechanisms of SZO-based thin films are dominated by ohmic conduction (hoping conduction) and Frenkel-Poole emission for the low resistance state (LRS) and the high resistance state (HRS), respectively. The turn-on process might be attributed to the formation of conducting filaments consisting of oxygen vacancies with the effective barrier height (phi(B,eff)) in the range of 0.10-0.13 eV, whereas the turn-off process might result from thermally assisted oxidation of oxygen vacancies by the Joule heating effect. Furthermore, the introduction of the high valence cation (V(5+)) in a Zr(4+) site of SZO crystalline structure can suppress the formation of oxygen vacancies due to the charge neutrality restriction. Such suppression leads to the changes in the forming voltage, turn-on voltage, HRS resistance, dielectric constant, and phi(B,eff) with vanadium doping concentration up to 0.2 mol%, which is within the solid solubility limit based on our measured lattice constants and Vegard's law.
Effects of Vanadium Doping on Resistive Switching Characteristics and Mechanisms of SrZrO3-Based Memory Films
(2010-08-01)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The effects of vanadium doping on resistive switching (RS) characteristics and mechanisms of RF-sputtered SrZrO3 (SZO)-based thin films are investigated in this paper. The physical and electrical properties of SZO-based thin films are modulated by vanadium doping due to the Zr4+ ion replaced by V5+, further affecting the RS parameters of SZO-based thin films. The conduction mechanisms of SZO-based thin films are dominated by ohmic conduction (hoping conduction) and Frenkel-Poole emission for the low resistance state (LRS) and the high resistance state (HRS), respectively. The turn-on process might be attributed to the formation of conducting filaments consisting of oxygen vacancies with the effective barrier height (phi(B,eff)) in the range of 0.10-0.13 eV, whereas the turn-off process might result from thermally assisted oxidation of oxygen vacancies by the Joule heating effect. Furthermore, the introduction of the high valence cation (V5+) in a Zr4+ site of SZO crystalline structure can suppress the formation of oxygen vacancies due to the charge neutrality restriction. Such suppression leads to the changes in the forming voltage, turn-on voltage, HRS resistance, dielectric constant, and phi(B,eff) with vanadium doping concentration up to 0.2 mol%, which is within the solid solubility limit based on our measured lattice constants and Vegard's law.
High Device Yield of Resistive Switching Characteristics in Oxygen-Annealed SrZrO(3) Memory Devices
(2011-04-01)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Huang, Yi-Han
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
This paper reports the effects of rapid thermal annealing (RTA) on resistive switching (RS) characteristics and mechanisms of SrZrO(3) (SZO)-based memory devices. SZO thin films were deposited on LaNiO(3) (LNO) (100)/Pt/Ti/SiO(2)/Si using radio-frequency magnetron sputtering and were followed by an RTA process in N(2), Ar, and O(2) ambients, respectively, at various temperatures for improving RS performance. Experimental results indicate that an SZO device annealed in O(2) at 600 degrees C (O(2)-600) exhibits stable RS properties and has a high device yield (similar to 90%), a reliable retention characteristic (up to 1 x 10(6) s at 100 degrees C), and steady nondestructive readout properties (over 1.4 x 10(4) s at 100 degrees C). However, by increasing RTA temperature to more than 700 degrees C, random formation of LNO (110) precipitates on the bottom surface of SZO grains might shorten the effective thickness of the SZO thin films. Furthermore, a strong electric field possibly occurs at the region between Al top electrodes and low-resistivity LNO precipitates. It is speculated that an RS phenomenon, which occurs within SZO grains instead of on grain boundaries, easily leads to RS failure, further resulting in severe degradation of device yield in the O(2)-700 and O(2)-800 devices. When compared with other devices, O(2)-600 SZO memory devices exhibit highly reliable RS characteristics.
High Device Yield of Resistive Switching Characteristics in Oxygen-Annealed SrZrO3 Memory Devices
(2011-04-01)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Huang, Yi-Han
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
This paper reports the effects of rapid thermal annealing (RTA) on resistive switching (RS) characteristics and mechanisms of SrZrO3 (SZO)-based memory devices. SZO thin films were deposited on LaNiO3 (LNO) (100)/Pt/Ti/SiO2/Si using radio-frequency magnetron sputtering and were followed by an RTA process in N-2, Ar, and O-2 ambients, respectively, at various temperatures for improving RS performance. Experimental results indicate that an SZO device annealed in O-2 at 600 degrees C (O-2-600) exhibits stable RS properties and has a high device yield (similar to 90%), a reliable retention characteristic (up to 1 x 10(6) s at 100 degrees C), and steady nondestructive readout properties (over 1.4 x 10(4) s at 100 degrees C). However, by increasing RTA temperature to more than 700 degrees C, random formation of LNO (110) precipitates on the bottom surface of SZO grains might shorten the effective thickness of the SZO thin films. Furthermore, a strong electric field possibly occurs at the region between Al top electrodes and low-resistivity LNO precipitates. It is speculated that an RS phenomenon, which occurs within SZO grains instead of on grain boundaries, easily leads to RS failure, further resulting in severe degradation of device yield in the O-2-700 and O-2-800 devices. When compared with other devices, O-2-600 SZO memory devices exhibit highly reliable RS characteristics.
High-speed and localized resistive switching characteristics of double-layer SrZrO(3) memory devices
(2010-07-28)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Huang, Chun-Yang
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The fabrication of SrZrO(3) (SZO) memory devices with oxygen-rich (OR) and oxygen-deficient (OD) double layers, their resistive switching (RS) characteristics and mechanisms are investigated in this study. Due to the difference in oxygen content between the OR and OD layers formed by an oxygen flow control (OFC) process during SZO deposition, the RS region is effectively reduced and localized within the OR layer, which leads to a low operation voltage and stable RS behaviours. Furthermore, the OFC SZO device exhibits high-speed switching (10 ns) over 400 times and long retention (>10(6) s), showing promising potential for next-generation nonvolatile memory applications.
High-speed and localized resistive switching characteristics of double-layer SrZrO3 memory devices
(2010-07-28)
Lin, Meng-Han
;
Wu, Ming-Chi
;
Huang, Chun-Yang
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The fabrication of SrZrO3 (SZO) memory devices with oxygen-rich (OR) and oxygen-deficient (OD) double layers, their resistive switching (RS) characteristics and mechanisms are investigated in this study. Due to the difference in oxygen content between the OR and OD layers formed by an oxygen flow control (OFC) process during SZO deposition, the RS region is effectively reduced and localized within the OR layer, which leads to a low operation voltage and stable RS behaviours. Furthermore, the OFC SZO device exhibits high-speed switching (10 ns) over 400 times and long retention (>10(6) s), showing promising potential for next-generation nonvolatile memory applications.
Highly Stable SrZrO3 Bipolar Resistive Switching Memory by Ti Modulation Layer
(2010)
Wu, Ming-Chi
;
Lin, Meng-Han
;
Yeh, Yu-Ting
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
In this study, we investigated the resistive switching characteristics of the SrZrO3 (SZO)-based resistance random access memory (RRAM). After the sequential thin-films Pt/Ti/SZO/LaNiO3 deposition, the post annealing (PA) treatment under various conditions was carried out to form the interfacial layer (TiOx) between Ti and SZO. It can be proved that the Ti modulation layer act as an oxygen getter can modify the resistive switching property of RRAM. With the suitable thickness of Ti layer and the proper annealing temperature, the SZO-based RRAM device could have a lower operation voltage, a lower compliance current a long retention behavior, and stable resistance ratio over 10(4) s under 0.3 V reading voltage.
Improvement of resistive switching characteristics in SrZrO3 thin films with embedded Cr layer
(2008-10-01)
Lin, Chih-Yang
;
Lin, Meng-Han
;
Wu, Ming-Chi
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The stabilization of the resistive switching properties is necessary to realize the memory application of the SrZrO3 (SZO)-based resistive switching devices. During continuous resistive switching cycle, broad variations of the resistive switching parameters of the SZO-based memory devices can be improved by a thin embedded Cr layer. The Cr metal layer is proposed to diffuse into and dope the SZO thin film to produce the space charge region, further reducing the effective resistive switching region. Hence, the good stabilization of the resistive switching properties can be obtained in the SZO films with embedded Cr layer.
Nonpolar Bistable Resistive Switching Behaviors of Bismuth Titanate Oxide Thin Film
(2009)
Lin, Meng-Han
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Wu, Ming-Chi
;
Lin, Chun-Chieh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Nonpolar bistable resistive switching behaviors of sol-gel derived bismuth titanate oxide (BTO) thin film are investigated in this study. The BTO thin film memory device without thermal treatment shows higher resistance ratio (similar to 10(4)) than the other annealed devices. The resistive switching behavior of the Pt/BTO/LNO/Pt device is reproducible and can be traced over 100 times. Both low resistance state (ON-state) and high resistance state (OFF-state) are stable over 10(4) s under 0.3 V voltage stress at room temperature (RT) and 85 degrees C. The retention behaviors of both memory states in the Pt/BTO/LNO/Pt device are very stable over 2 x 10(6) s at RT and 85 degrees C, showing that the BTO thin film memory device is a good candidate for nonvolatile memory application
Voltage-polarity-independent and high-speed resistive switching properties of v-doped SrZrO3 thin films
(2007-12-01)
Lin, Chun-Chieh
;
Lin, Chih-Yang
;
Lin, Meng-Han
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
In this paper, nonpolar resistive switching behavior is reported for the first time in a SZO-based memory device. The electrode materials used which have different conductivities affect the resistive switching properties of the device. The A1/V:SZO-LNO/Pt device shows nonpolar switching behavior, whereas the A1/V:SZO/LNO device has bipolar switching property. The resistance ratios of these two devices are quite distinct owing to the difference between the resistance of low resistance states. The A1/V:SZO-LNO/Pt device with lower resistive switching voltages (+/- 7 V turn on and 2 V turn off) and higher resistance ratio (10(7)) is more suitable for practical applications compared to the A1/V:SZO/LNO device. The switching speed of the A1/V:SZO-LNO/Pt device is 10 ns, which is the fastest speed that has ever been reported. The conduction mechanisms, nondestructive readout property, retention time, and endurance of this device are also reported in this paper.