Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393273
Y. Noguchi, Y. Chishima, M. Tamada, M. Miyayama
Single crystals of PbTiO3 (PT) and BiFeO3(BFO) were grown by a self-flux method, and the influence of lattice defects on the leakage current properties at 25degC was investigated. While PT crystals annealed in air at 700degC showed a leakage current density of the order of 10-5 A/cm2 , annealing under a high oxygen partial pressure of 35 MPa at 700degC increased the leakage current density to 10-4 A/cm2 . This increase in leakage current by the oxidation treatment provides direct evidence that electron hole plays a dominant carrier for the leakage current property in the PT system. The conductivity at 800degC of the PT crystals proportionally increased with an increase in oxygen partial pressure, and electron hole is revealed to be a detrimental carrier even at 800degC. Thermogravimetric analysis showed that a larger weight loss due to PbO vaporization was observed under a higher oxygen partial pressure at high temperatures above 1000degC. The enhanced vacancy formation of Pb under a higher oxygen partial pressure demonstrates that the surface reaction between Pb atoms and O atoms adsorbed onto the PT surface, which leads to PbO (g), is the limiting factor for the vacancy formation in the PT system. It is suggested that Pb vacancies act as an electron acceptor for generating electron holes, leading to a higher leakage current. It is found that the mechanism of the leakage curren for BFO cyrstals is almost the same as that for PT crystals.
采用自通量法生长PbTiO3 (PT)和BiFeO3(BFO)单晶，研究了晶格缺陷对25℃下漏电流性能的影响。在700℃空气中退火的PT晶体泄漏电流密度为10-5 a /cm2，在700℃高氧分压(35 MPa)下退火的PT晶体泄漏电流密度为10-4 a /cm2。氧化处理导致的泄漏电流的增加直接证明了电子空穴是PT体系中泄漏电流的主要载体。PT晶体在800℃时的电导率随氧分压的增加而成比例增加，即使在800℃时电子空穴也是有害的载流子。热重分析表明，在1000℃以上的高温条件下，较高的氧分压下，PbO汽化造成的失重较大。在较高的氧分压下，Pb的空位形成增强，说明吸附在PT表面的Pb原子与O原子之间的表面反应导致PbO (g)的生成，是PT体系中空位形成的限制因素。Pb空位作为电子受体产生电子空穴，导致更高的漏电流。研究发现，BFO晶体的漏电流形成机理与PT晶体基本相同。
{"title":"Influence of defects on the leakage current properties in PbTiO3 and BiFeO3 single crystals","authors":"Y. Noguchi, Y. Chishima, M. Tamada, M. Miyayama","doi":"10.1109/ISAF.2007.4393273","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393273","url":null,"abstract":"Single crystals of PbTiO3 (PT) and BiFeO3(BFO) were grown by a self-flux method, and the influence of lattice defects on the leakage current properties at 25degC was investigated. While PT crystals annealed in air at 700degC showed a leakage current density of the order of 10-5 A/cm2 , annealing under a high oxygen partial pressure of 35 MPa at 700degC increased the leakage current density to 10-4 A/cm2 . This increase in leakage current by the oxidation treatment provides direct evidence that electron hole plays a dominant carrier for the leakage current property in the PT system. The conductivity at 800degC of the PT crystals proportionally increased with an increase in oxygen partial pressure, and electron hole is revealed to be a detrimental carrier even at 800degC. Thermogravimetric analysis showed that a larger weight loss due to PbO vaporization was observed under a higher oxygen partial pressure at high temperatures above 1000degC. The enhanced vacancy formation of Pb under a higher oxygen partial pressure demonstrates that the surface reaction between Pb atoms and O atoms adsorbed onto the PT surface, which leads to PbO (g), is the limiting factor for the vacancy formation in the PT system. It is suggested that Pb vacancies act as an electron acceptor for generating electron holes, leading to a higher leakage current. It is found that the mechanism of the leakage curren for BFO cyrstals is almost the same as that for PT crystals.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114203774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393167
B. Trinh, S. Horita
The nondestructive readout characteristics of the ferroelectric gate field-effect transistor (F-FET) memory with an intermediate electrode for data writing (IF-FET) was investigated by using the conventional and the new writing and reading methods. Normally, for the conventional writing, we use two positive or negative square pulses to induce the positive (Pr+) or the negative (Pr-) remnant polarizations, respectively. For the conventional reading, unipolar square pulses were applied. Although the difference in output voltages between Pr+ and Pr- is large, the nondestructive readout characteristic for the Pr- is poor because the Pr- memory state is quickly degraded after each reading due to non-reswitched or nonreturned domains. Therefore, for the new writing, we proposed a new memory state, Pr0, instead of Pr-. The Pr0 was induced by a combined pulse with a positive part (Vw+) and a negative part (Vw-). For the new reading, a negative voltage (VR-) was applied, following a positive voltage (VR+) to recover the memory state to the initial one. By optimizing the Vw- and the VR- in the new method, the nondestructive readout is further improved, compared with the conventional method.
{"title":"Improvement of Nondestructive Readout of Ferroelectric Gate FET Memory with an Intermediate Electrode by using New Data Writing and Reading Methods","authors":"B. Trinh, S. Horita","doi":"10.1109/ISAF.2007.4393167","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393167","url":null,"abstract":"The nondestructive readout characteristics of the ferroelectric gate field-effect transistor (F-FET) memory with an intermediate electrode for data writing (IF-FET) was investigated by using the conventional and the new writing and reading methods. Normally, for the conventional writing, we use two positive or negative square pulses to induce the positive (Pr<sup>+</sup>) or the negative (Pr<sup>-</sup>) remnant polarizations, respectively. For the conventional reading, unipolar square pulses were applied. Although the difference in output voltages between Pr<sup>+</sup> and Pr<sup>-</sup> is large, the nondestructive readout characteristic for the Pr<sup>-</sup> is poor because the Pr<sup>-</sup> memory state is quickly degraded after each reading due to non-reswitched or nonreturned domains. Therefore, for the new writing, we proposed a new memory state, Pr<sub>0</sub>, instead of Pr<sup>-</sup>. The Pr<sup>0</sup> was induced by a combined pulse with a positive part (V<sub>w</sub> <sup>+</sup>) and a negative part (V<sub>w</sub> <sup>-</sup>). For the new reading, a negative voltage (V<sub>R</sub> <sup>-</sup>) was applied, following a positive voltage (V<sub>R</sub> <sup>+</sup>) to recover the memory state to the initial one. By optimizing the V<sub>w</sub> <sup>-</sup> and the V<sub>R</sub> <sup>-</sup> in the new method, the nondestructive readout is further improved, compared with the conventional method.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121479229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393246
C. Sung, Y.J. Huang, J. Lai, G. Hwang
Multiphase suspensions systems are extensively used in hydrology, biochemical, and food industry. Ultrasonic spectroscopy is a rapid, on-line, and non-invasive measurement technique for the characterization of suspension over a wide range of particle size and concentration. Although kaolin has already been investigated extensively the ultrasonic attenuation property of kaolin against concentration with various temperatures has not been reported yet. This paper provides a series measurement results of ultrasonic attenuation of kaolin under a wide range of concentrations (0 ~ 300,000 ppm) and various temperatures (5 ~ 25degC). Besides, the ultrasonic attenuation of silt of Shihmen reservoir in Taiwan has been measured. The mean radii for the silt ranged from 4 to 8 mum. Results show that the variation of attenuation is driven by concentration and temperature. Based on these results as calibration data, an ultrasonic system is then designed and manufactured for real-time monitoring the silt concentration of the Shihmen reservoir.
{"title":"Ultrasonic attenuation in solutions of kaolin and samples from reservoir with various thermal conditions","authors":"C. Sung, Y.J. Huang, J. Lai, G. Hwang","doi":"10.1109/ISAF.2007.4393246","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393246","url":null,"abstract":"Multiphase suspensions systems are extensively used in hydrology, biochemical, and food industry. Ultrasonic spectroscopy is a rapid, on-line, and non-invasive measurement technique for the characterization of suspension over a wide range of particle size and concentration. Although kaolin has already been investigated extensively the ultrasonic attenuation property of kaolin against concentration with various temperatures has not been reported yet. This paper provides a series measurement results of ultrasonic attenuation of kaolin under a wide range of concentrations (0 ~ 300,000 ppm) and various temperatures (5 ~ 25degC). Besides, the ultrasonic attenuation of silt of Shihmen reservoir in Taiwan has been measured. The mean radii for the silt ranged from 4 to 8 mum. Results show that the variation of attenuation is driven by concentration and temperature. Based on these results as calibration data, an ultrasonic system is then designed and manufactured for real-time monitoring the silt concentration of the Shihmen reservoir.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126333485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393288
H. Naganuma, N. Shimura, H. Shima, S. Yasui, K. Nishida, T. Iijima, H. Funakubo, S. Okamura
BiFeO3-BiCoO3 solid solution films were fabricated by a chemical solution deposition (CSD) method onto the Pt/Ti/SiO2/Si(100) substrates followed by a post-deposition annealing at 873 K for 10 min. X-ray diffraction measurements indicate the apparent phase transition of the Bi(CoxFe1-times)O3 solid solution films by increasing the cobalt composition were take place at the cobalt composition of around x = 0.2 and 0.4, respectively. According to the D-E hysteresis measurements, the ferroelectricity observed at the cobalt composition less than x = 0.3 indicating that the MPB has a possibility to exist at these composition region.
{"title":"Structural and ferroelectric properties of BiFeO3-BiCoO3 solid solution films","authors":"H. Naganuma, N. Shimura, H. Shima, S. Yasui, K. Nishida, T. Iijima, H. Funakubo, S. Okamura","doi":"10.1109/ISAF.2007.4393288","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393288","url":null,"abstract":"BiFeO3-BiCoO3 solid solution films were fabricated by a chemical solution deposition (CSD) method onto the Pt/Ti/SiO2/Si(100) substrates followed by a post-deposition annealing at 873 K for 10 min. X-ray diffraction measurements indicate the apparent phase transition of the Bi(CoxFe1-times)O3 solid solution films by increasing the cobalt composition were take place at the cobalt composition of around x = 0.2 and 0.4, respectively. According to the D-E hysteresis measurements, the ferroelectricity observed at the cobalt composition less than x = 0.3 indicating that the MPB has a possibility to exist at these composition region.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126398943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393151
S. Summerfelt, T. Moise, K. Udayakumar, K. Boku, K. Remack, J. Rodriguez, J. Gertas, H. McAdams, S. Madan, J. Eliason, J. Groat, D. Kim, P. Staubs, M. Depner, R. Bailey
Ferroelectric memories are the most promising alternative to traditional embedded nonvolatile memories, such as flash and EEPROMs, because of their fast read/write cycle time, non-volatile data retention, low voltage/low power operation and low number of additional masks for fabrication (+2). An embedded ferroelectric memory (FRAM) has been developed using a 1.5 V, 130 nm 5 metal layer Cu/FSG logic process. The only modification to the logic process was the addition of a ferroelectric process module consisting of two additional masks (FECAP, VIAO) immediately before MET1. The ferroelectric was 70 nm Pb(Zr,Ti)O3 (PZT) deposited by metalorganic chemical vapor deposition (MOCVD). The electrical properties of a 8 Mb 1T-1C embedded FRAM were characterized. This eFRAM process has been used to simultaneously fabricate a digital signal processor (DSP) using the eFRAM process flow and the operating frequency is nearly the same relative to the CMOS baseline. This eFRAM process flow creates a technology platform that enables ultra-low-power devices.
{"title":"High-Density 8Mb 1T-1C Ferroelectric Random Access Memory Embedded Within a Low-Power 130nm Logic Process","authors":"S. Summerfelt, T. Moise, K. Udayakumar, K. Boku, K. Remack, J. Rodriguez, J. Gertas, H. McAdams, S. Madan, J. Eliason, J. Groat, D. Kim, P. Staubs, M. Depner, R. Bailey","doi":"10.1109/ISAF.2007.4393151","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393151","url":null,"abstract":"Ferroelectric memories are the most promising alternative to traditional embedded nonvolatile memories, such as flash and EEPROMs, because of their fast read/write cycle time, non-volatile data retention, low voltage/low power operation and low number of additional masks for fabrication (+2). An embedded ferroelectric memory (FRAM) has been developed using a 1.5 V, 130 nm 5 metal layer Cu/FSG logic process. The only modification to the logic process was the addition of a ferroelectric process module consisting of two additional masks (FECAP, VIAO) immediately before MET1. The ferroelectric was 70 nm Pb(Zr,Ti)O3 (PZT) deposited by metalorganic chemical vapor deposition (MOCVD). The electrical properties of a 8 Mb 1T-1C embedded FRAM were characterized. This eFRAM process has been used to simultaneously fabricate a digital signal processor (DSP) using the eFRAM process flow and the operating frequency is nearly the same relative to the CMOS baseline. This eFRAM process flow creates a technology platform that enables ultra-low-power devices.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130191985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393294
A. Iwata, J. Akedo
PZT films were deposited on 4 inch silicon wafer substrate by aerosol deposition, based on room temperature impact consolidation (RTIC). A nozzle that blowed out aerosol beam scanned the wafer. The film thickness was evaluated through the measurements with step height of masked edges. The aerosol deposited films showed relatively good uniformity of thickness of 1.4%. The surface roughness was Ra 59 nm.
{"title":"Thickness Uniformity of Large Area PZT Films Formed by Aerosol Deposition","authors":"A. Iwata, J. Akedo","doi":"10.1109/ISAF.2007.4393294","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393294","url":null,"abstract":"PZT films were deposited on 4 inch silicon wafer substrate by aerosol deposition, based on room temperature impact consolidation (RTIC). A nozzle that blowed out aerosol beam scanned the wafer. The film thickness was evaluated through the measurements with step height of masked edges. The aerosol deposited films showed relatively good uniformity of thickness of 1.4%. The surface roughness was Ra 59 nm.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134217383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393195
Masayuki Toda, Y. Sasaki, Y. Kurihashi, M. Umeda, M. Fukagawa, M. Tamura, Y. Kosugi, M. Kusuhara
The mass production system of MOCVD, which has the originally designed vaporizer and liquid source delivery system, has been developed for FeRAM-LSI, DRAM-LSI and so on. In this work, the thin film formations of ferroelectric materials Bi3Nd1Ti3O12 (BNT), high-k materials SrTiO3 (STO) and Nb-doped SrTiO3(Nb-STO) by newly developed MOCVD system were extensively examined.
{"title":"Thin Film Formations of Ferroelectric Material Bi3Nd1Ti3O12 (BNT), High-k Materials SrTiO3 (STO) and Nb-doped SrTiO3(Nb-STO) by Newly Developed MOCVD System","authors":"Masayuki Toda, Y. Sasaki, Y. Kurihashi, M. Umeda, M. Fukagawa, M. Tamura, Y. Kosugi, M. Kusuhara","doi":"10.1109/ISAF.2007.4393195","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393195","url":null,"abstract":"The mass production system of MOCVD, which has the originally designed vaporizer and liquid source delivery system, has been developed for FeRAM-LSI, DRAM-LSI and so on. In this work, the thin film formations of ferroelectric materials Bi<sub>3</sub>Nd<sub>1</sub>Ti<sub>3</sub>O<sub>12</sub> (BNT), high-k materials SrTiO<sub>3</sub> (STO) and Nb-doped SrTiO<sub>3</sub>(Nb-STO) by newly developed MOCVD system were extensively examined.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134448912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393244
K. Kubo, M. Echizen, T. Nishida, T. Takeda, K. Uchiyama, T. Shiosaki
Ferroelectric lead zirconium titanate (PZT) has been used in FeRAMs, which are expected to become common large capacity devices. We have extensively studied PZT thin films and their micro-processing. However, there are several problems of degradation by crystal defects at grain boundaries in thin films and surface damage by microfabrication. Self-assembled nanocrystals are useful for solving these problems. However, position control in nanocrystal growth is very difficult. Thus, atomically flat substrates and RF magnetron sputtering together are used for better position control. RF magnetron sputtering stimulates nucleation of crystals because the sputtered particles impinge on substrates with high energy. We grew PZT nanocrystals on alpha-Al2O3 (001) single crystalline substrate surfaces. Atomic force microscopy observations indicated that triangular-shaped crystals were formed on the substrates.
{"title":"Synthesis and Characterization of PZT Ferroelectric Nanocrystals Current Measurement","authors":"K. Kubo, M. Echizen, T. Nishida, T. Takeda, K. Uchiyama, T. Shiosaki","doi":"10.1109/ISAF.2007.4393244","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393244","url":null,"abstract":"Ferroelectric lead zirconium titanate (PZT) has been used in FeRAMs, which are expected to become common large capacity devices. We have extensively studied PZT thin films and their micro-processing. However, there are several problems of degradation by crystal defects at grain boundaries in thin films and surface damage by microfabrication. Self-assembled nanocrystals are useful for solving these problems. However, position control in nanocrystal growth is very difficult. Thus, atomically flat substrates and RF magnetron sputtering together are used for better position control. RF magnetron sputtering stimulates nucleation of crystals because the sputtered particles impinge on substrates with high energy. We grew PZT nanocrystals on alpha-Al2O3 (001) single crystalline substrate surfaces. Atomic force microscopy observations indicated that triangular-shaped crystals were formed on the substrates.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134168197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393201
S. Kim, Sang Young Lee, Sang Woon Lee, C. Hwang
Ru thin films were grown on TiO2/Si and bare-Si substrates by atomic-layer-deposition using 2,4-(dimethylpentadienyl)(ethylcyclopentadienyl)Ru and O2 as Ru precursor and reactant, respectively. Negligible RuO2 was formed even with an excessive oxygen dose. Ru films on TiO2/Si substrate showed smoother surface morphology compared to Ru films on bare-Si substrate. Although abnormal grain growth of Ru films appeared at annealing temperature > 700degC, agglomeration of Ru films was not observed. Al-incorporated TiO2 (ATO) films were grown on Ru films and the electrical properties of the capacitor were investigated in order to evaluate the properties of bottom Ru films. The leakage current density of an ATO film with an equivalent oxide thickness of 0.7 nm was 10-7 A/cm2 at + 1 V. Therefore, Ru films grown by ALD are very promising as the capacitor electrodes of future dynamic random access memories.
{"title":"Atomic Layer Deposition of Ru Thin Films Using 2,4-(dimethylpentadienyl)(ethylcyclopentadienyl) Ru by a Liquid Injection System","authors":"S. Kim, Sang Young Lee, Sang Woon Lee, C. Hwang","doi":"10.1109/ISAF.2007.4393201","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393201","url":null,"abstract":"Ru thin films were grown on TiO2/Si and bare-Si substrates by atomic-layer-deposition using 2,4-(dimethylpentadienyl)(ethylcyclopentadienyl)Ru and O2 as Ru precursor and reactant, respectively. Negligible RuO2 was formed even with an excessive oxygen dose. Ru films on TiO2/Si substrate showed smoother surface morphology compared to Ru films on bare-Si substrate. Although abnormal grain growth of Ru films appeared at annealing temperature > 700degC, agglomeration of Ru films was not observed. Al-incorporated TiO2 (ATO) films were grown on Ru films and the electrical properties of the capacitor were investigated in order to evaluate the properties of bottom Ru films. The leakage current density of an ATO film with an equivalent oxide thickness of 0.7 nm was 10-7 A/cm2 at + 1 V. Therefore, Ru films grown by ALD are very promising as the capacitor electrodes of future dynamic random access memories.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131787066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393401
M. Fukuda, M. Nishihira, K. Imano
A new system for detecting the sub-harmonic component of ultrasonic pulse wave is constructed. Double-layered piezoelectric transducer (DLPT) [1] which has the identical polarization directions is for the detection. The resonance frequency of the DLPT comprised of two transducers (with resonance frequency of f) is equal to f when the transducers are electrically connected in parallel and to f/2 when the transducers are connected in series connection. The performance of the DLPT used in this ultrasonic system is described. As the experimental results, the efficient detection of the sub-harmonic component of the ultrasonic pulse wave reflected by a reflector is successfully accomplished. On contrary, the sub-harmonic component could not be detected by using conventional system without an electrical switch for elctrical connection of the DLPT.
{"title":"A New Detection Method for Sub-Harmonic Components Using a Double-Layered Piezoelectric Transducer","authors":"M. Fukuda, M. Nishihira, K. Imano","doi":"10.1109/ISAF.2007.4393401","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393401","url":null,"abstract":"A new system for detecting the sub-harmonic component of ultrasonic pulse wave is constructed. Double-layered piezoelectric transducer (DLPT) [1] which has the identical polarization directions is for the detection. The resonance frequency of the DLPT comprised of two transducers (with resonance frequency of f) is equal to f when the transducers are electrically connected in parallel and to f/2 when the transducers are connected in series connection. The performance of the DLPT used in this ultrasonic system is described. As the experimental results, the efficient detection of the sub-harmonic component of the ultrasonic pulse wave reflected by a reflector is successfully accomplished. On contrary, the sub-harmonic component could not be detected by using conventional system without an electrical switch for elctrical connection of the DLPT.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131007550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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