Browsing by Author "Leu, Ching-Chich"

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Effects of HfO(2) buffer layer thickness on the properties of Pt/SrBi(2)Ta(2)O(9)//HfO(2)/Si structure
(2008-07-01)
Leu, Ching-Chich
;
Lin, Chen-Han
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
電子工程學系及電子研究所
We investigated structural and characteristic changes in thin HfO(2) films (< 10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi(2)Ta(2)O(9)/HfO(2)/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO(2) films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO(2) as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO(2) limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.
Effects of HfO2 buffer layer thickness on the properties of Pt/SrBi2Ta2O9//HfO2/Si structure
(2008-07-01)
Leu, Ching-Chich
;
Lin, Chen-Han
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
電子工程學系及電子研究所
We investigated structural and characteristic changes in thin HfO2 films (< 10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi2Ta2O9/HfO2/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO2 films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO2 as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO2 limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.
Influence of Ta content on the physical properties of SrBi2Ta2O9 ferroelectric thin films
(2006-12-01)
Hsu, Fan-Yi
;
Leu, Ching-Chich
;
Chien, Chao-Hsin
;
Hu, Chen-Ti
;
電子工程學系及電子研究所
We have investigated the effect that the Ta content has on the ferroelectric properties of strontium bismuth tantalate (SBT) thin films synthesized using metalorganic decomposition (MOD) and spin coating techniques. The physical properties of these SBT samples were strongly dependent upon the Ta ratio. Polarization measurements revealed that Ta-deficient SBT exhibited a relatively low coercive field (2E(c) similar to 87 kV/cm) and a high remanent polarization (2P(r) similar to 15 mu C/cm(2)). The value of 2P(r) decreased as the Ta ratio in SBT increased. The improved ferroelectric properties of the Ta-deficient SBT,,samples may have resulted from the uniformly well-grown bismuth-layered-structured (BLS) phases of the films and their highly preferential orientation along the a and b axes. We suggest that the. incorporation of Ta vacancies plays an important role in enhancing the crystallinities and microstructures of Ta-deficient SBT films.
Obtaining Lower Forming Voltage and Self-Compliance Current by Using a Nitride Gas/Indium-Tin Oxide Insulator in Resistive Random Access Memory
(2016-12)
Chen, Po-Hsun
;
Chang, Ting-Chang
;
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Pan, Chih-Hung
This paper investigates the characteristics of applying indium-tin oxide (ITO) with and without nitride gas (N-2) as the insulator in resistive random access memory (RRAM). After cosputtering an ITO target with N-2 as the insulator and capping the same ITO material as the top electrode, the device exhibits rectifier and resistance switching characteristics before and after the forming process, respectively. The Schottky diodelike rectifier mechanism was also verified by various temperature measurements. Furthermore, robust resistance switching at a positive forming voltage, smaller than that required during negative bias forming, can be achieved. Both positive and negative forming processes are examined with current fitting results, which show different dominant mechanisms when using positive or negative biases. All these mechanisms have also been verified by temperature effect experiments, which confirmed the dominant conduction mechanisms. This, in combination with the fact that the positive forming voltage itself is smaller than the negative forming voltage, and decreases with device scale down, provides two highly beneficial results. This good performance achieved by using ITO with N-2 suggests significant progress of RRAM and remarkable potential applications.
Properties of Pt/SrBi2Ta2O9/BL/Si MFIS structures containing HfO2, SiO2, and Si3N4 buffer layers
(2007)
Leu, Ching-Chich
;
Leu, Chia-Feng
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
Huang, Rui-Hao
The physical and electrical properties of Pt/SrBi2Ta2O9 (SBT)/buffer layer (BL)/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures incorporating HfO2, SiO2, and Si2N4 as buffer layers were investigated. When employing HfO2 as the buffer layer, an MFIS structure exhibiting a high memory ratio was constructed, presumably because of the SBT characteristics and the high quality of the HfO2 layer on the Si substrate. This study demonstrates that HfO2 is one of the best buffer-layer materials for ferroelectric memory applications. (c) 2007 The Electrochemical Society.