Pub Date : 1900-01-01DOI: 10.1109/RELPHY.1998.670475
J. Ebel, C. Bozada, T. Schlesinger, C. Cerny, G. Desalvo, R. Dettmer, J. Gillespie, T. Jenkins, K. Nakano, C. Pettiford, T. Quach, J. Sewell, G. Via, R. Welch
We have developed and demonstrated new techniques for failure analysis based on focused ion beam (FIB) cross-sectioning and inspection by atomic force microscopy (AFM). Normally, inspection after FIB cross-sectioning is done by scanning electron microscopy (SEM). As features of interest shrink below limits detectable by SEM, often the next method chosen is transmission electron microscopy (TEM). However, sample preparation for site-specific TEM is difficult and time-consuming, even using newer methods based on FIB milling. AFM offers higher resolution imaging than SEM, and relaxes many of the sample preparation constraints of TEM. The AFM/FIB technique has been demonstrated on GaAs-AlGaAs and GaAs-InGaP heterojunction bipolar transistors (HBTs), including devices which have been electrically stressed to failure.
{"title":"Cross-sectional atomic force microscopy of focused ion beam milled devices","authors":"J. Ebel, C. Bozada, T. Schlesinger, C. Cerny, G. Desalvo, R. Dettmer, J. Gillespie, T. Jenkins, K. Nakano, C. Pettiford, T. Quach, J. Sewell, G. Via, R. Welch","doi":"10.1109/RELPHY.1998.670475","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670475","url":null,"abstract":"We have developed and demonstrated new techniques for failure analysis based on focused ion beam (FIB) cross-sectioning and inspection by atomic force microscopy (AFM). Normally, inspection after FIB cross-sectioning is done by scanning electron microscopy (SEM). As features of interest shrink below limits detectable by SEM, often the next method chosen is transmission electron microscopy (TEM). However, sample preparation for site-specific TEM is difficult and time-consuming, even using newer methods based on FIB milling. AFM offers higher resolution imaging than SEM, and relaxes many of the sample preparation constraints of TEM. The AFM/FIB technique has been demonstrated on GaAs-AlGaAs and GaAs-InGaP heterojunction bipolar transistors (HBTs), including devices which have been electrically stressed to failure.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127322115","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670459
A. Bonfiglio, M. Casu, M. Vanzi, F. Magistrali, M. Maini, G. Salmini
Recombination-enhanced-defect-reaction (REDR) (Kymerling, Solid State Electron. vol 21, pp. 1391-1401, 1978) has been recently proposed (Magistrali et al. 1997) as the driving mechanism for sudden failures in 980 nm SL SQW InGaAs pump laser diodes for active fiber optics. The proposal follows a set of observations on life-tested devices that coherently lead to link the ultimate catastrophic failure to the growth of line defects from outside to inside the active layer. The most intriguing feature of the detected failure mode remains its sudden occurrence during constant-current life-tests, which is the total loss of the laser emission within a few tens of hours, after several hundred hours of perfectly regular operation. No correlation has ever been found between the occurence of that phenomenon and any of the many initial measurements that have been performed. The paper aims to account for the observed kinetics, based on the simple model of a native ideal point defect located within a few diffusion lengths from the edge of the depleted region of a laser diode. Its effect on the laser current is quantified, as well as the energy released to the lattice per unit time because of recombination at the defect neighbourhoods. The key point is to correlate that energy with some growth direction and speed, which leads to a model for the degradation kinetics.
重组增强缺陷反应(REDR) (Kymerling，固态电子。最近(Magistrali et al. 1997)提出了用于有源光纤的980 nm SL SQW InGaAs泵浦激光二极管突然失效的驱动机制。该提案遵循了对经过寿命测试的设备的一系列观察，这些观察一致地将最终的灾难性故障与从外部到内部的线路缺陷的增长联系起来。检测到的故障模式最有趣的特征是它在恒流寿命测试期间突然发生，即经过数百小时的完全正常运行后，在几十小时内激光发射完全丧失。这种现象的发生与许多已经进行的初步测量之间没有任何关联。本文的目的是解释观察到的动力学，基于一个简单的模型，一个天然的理想点缺陷位于几个扩散长度从激光二极管的耗尽区边缘。它对激光电流的影响是量化的，以及每单位时间释放到晶格的能量，因为在缺陷邻域重组。关键是将能量与某些生长方向和速度联系起来，从而得到降解动力学模型。
{"title":"REDR-based kinetics for line defects leading to sudden failures in 980 nm SL SQW InGaAs laser diodes","authors":"A. Bonfiglio, M. Casu, M. Vanzi, F. Magistrali, M. Maini, G. Salmini","doi":"10.1109/RELPHY.1998.670459","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670459","url":null,"abstract":"Recombination-enhanced-defect-reaction (REDR) (Kymerling, Solid State Electron. vol 21, pp. 1391-1401, 1978) has been recently proposed (Magistrali et al. 1997) as the driving mechanism for sudden failures in 980 nm SL SQW InGaAs pump laser diodes for active fiber optics. The proposal follows a set of observations on life-tested devices that coherently lead to link the ultimate catastrophic failure to the growth of line defects from outside to inside the active layer. The most intriguing feature of the detected failure mode remains its sudden occurrence during constant-current life-tests, which is the total loss of the laser emission within a few tens of hours, after several hundred hours of perfectly regular operation. No correlation has ever been found between the occurence of that phenomenon and any of the many initial measurements that have been performed. The paper aims to account for the observed kinetics, based on the simple model of a native ideal point defect located within a few diffusion lengths from the edge of the depleted region of a laser diode. Its effect on the laser current is quantified, as well as the energy released to the lattice per unit time because of recombination at the defect neighbourhoods. The key point is to correlate that energy with some growth direction and speed, which leads to a model for the degradation kinetics.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122097882","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670453
A. Bandyopadhyay, S. Subramanian, S. Chandrasekhar, S. Goodnick
The DC characteristics of InGaAs-InP single heterojunction bipolar transistors (SHBTs) were studied for the first time under high energy (/spl sim/1 MeV) electron radiation with a cumulative dose up to 5.4/spl times/10/sup 15/ electrons/cm/sup 2/. The following degradation effects were observed for electron doses greater than 10/sup 15//cm/sup 2/: (1) decrease in collector current, (2) decrease in current gain by up to 50%, and (3) an increase in collector saturation voltage by 0.2-0.8 V depending on base current. The increase in collector saturation voltage is attributed to an increase in emitter contact resistance after irradiation. The degradation of collector current and current gain are thought to be due to increased recombination caused by radiation-induced defects in the base-emitter junction.
{"title":"Degradation of InGaAs-InP heterojunction bipolar transistors under high energy electron irradiation","authors":"A. Bandyopadhyay, S. Subramanian, S. Chandrasekhar, S. Goodnick","doi":"10.1109/RELPHY.1998.670453","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670453","url":null,"abstract":"The DC characteristics of InGaAs-InP single heterojunction bipolar transistors (SHBTs) were studied for the first time under high energy (/spl sim/1 MeV) electron radiation with a cumulative dose up to 5.4/spl times/10/sup 15/ electrons/cm/sup 2/. The following degradation effects were observed for electron doses greater than 10/sup 15//cm/sup 2/: (1) decrease in collector current, (2) decrease in current gain by up to 50%, and (3) an increase in collector saturation voltage by 0.2-0.8 V depending on base current. The increase in collector saturation voltage is attributed to an increase in emitter contact resistance after irradiation. The degradation of collector current and current gain are thought to be due to increased recombination caused by radiation-induced defects in the base-emitter junction.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129254803","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670444
T. Nigam, R. Degraeve, G. Groeseneken, M. Heyns, H. Maes
It is shown that the conventional interpretation of constant current Q/sub BD/ to evaluate the influence of process variations on the reliability of MOS structures can lead to erroneous conclusions. For a fixed thickness, the comparison of Q/sub BD/-distributions of all processes that affect the breakdown statistics becomes even meaningless. For ultra-thin oxides, the impact of different processing conditions requires constant gate voltage instead of constant current density Q/sub BD/-tests.
{"title":"Constant current charge-to-breakdown: Still a valid tool to study the reliability of MOS structures?","authors":"T. Nigam, R. Degraeve, G. Groeseneken, M. Heyns, H. Maes","doi":"10.1109/RELPHY.1998.670444","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670444","url":null,"abstract":"It is shown that the conventional interpretation of constant current Q/sub BD/ to evaluate the influence of process variations on the reliability of MOS structures can lead to erroneous conclusions. For a fixed thickness, the comparison of Q/sub BD/-distributions of all processes that affect the breakdown statistics becomes even meaningless. For ultra-thin oxides, the impact of different processing conditions requires constant gate voltage instead of constant current density Q/sub BD/-tests.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"259 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125953325","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670562
Y. Huh, M.G. Lee, J. Lee, H. Jung, T. Li, D. Song, Y. Lee, J. Hwang, Y. Sung, S. Kang
ESD-induced latent damage in CMOS integrated circuits has been thoroughly investigated after cumulative low-level ESD stress. A study of the latent damage for transistors at the package level has been performed with various kinds of ESD stress modes. The impact of latent damage on circuit performance degradation was also evaluated using a 64 Mb DRAM chip as a DUT.
{"title":"A study of ESD-induced latent damage in CMOS integrated circuits","authors":"Y. Huh, M.G. Lee, J. Lee, H. Jung, T. Li, D. Song, Y. Lee, J. Hwang, Y. Sung, S. Kang","doi":"10.1109/RELPHY.1998.670562","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670562","url":null,"abstract":"ESD-induced latent damage in CMOS integrated circuits has been thoroughly investigated after cumulative low-level ESD stress. A study of the latent damage for transistors at the package level has been performed with various kinds of ESD stress modes. The impact of latent damage on circuit performance degradation was also evaluated using a 64 Mb DRAM chip as a DUT.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132097440","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670509
W. Jiang, H. Le, J. Chung, T. Kopley, P. Marcoux, C. Dai
The major factors that cumulatively determine circuit-level hot-carrier reliability are defined and characterized in this paper. The inherent inverse relationship between lifetime-underestimation/criteria-overspecification and the amount of known device/circuit information is explored. Lifetime-underestimation/criteria-overspecification is shown to depend quite strongly on the particular "worst-case" approximations used.
{"title":"Assessing circuit-level hot-carrier reliability","authors":"W. Jiang, H. Le, J. Chung, T. Kopley, P. Marcoux, C. Dai","doi":"10.1109/RELPHY.1998.670509","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670509","url":null,"abstract":"The major factors that cumulatively determine circuit-level hot-carrier reliability are defined and characterized in this paper. The inherent inverse relationship between lifetime-underestimation/criteria-overspecification and the amount of known device/circuit information is explored. Lifetime-underestimation/criteria-overspecification is shown to depend quite strongly on the particular \"worst-case\" approximations used.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132441557","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670672
F. Arai, T. Maruyama, R. Shirota
Using 16 Mbit flash memories, we clarified the relationship between data retention and Si surface micro-defects just before the tunnel oxidation process. After 10/sup 5/ to 10/sup 6/ write/erase cycles, a small number of singular cells appear to have an anomalously large charge loss rate, when the Si surface defect density due to process damage exceeds 1.2/spl times/10/sup 20//cm/sup 3/. This anomalous charge loss phenomenon strongly depends on the electric field in the tunnel oxide, which is caused by the stored charge in the floating gate. Thus, an accelerated data retention test can be performed by means of the electric field in the tunnel oxide, by controlling the programmed V/sub t/ to be more than 2.4 V just before the retention test (here, neutral V/sub t/ is adjusted to 0 V). By using an accelerated test, it is clarified that controlling the number of surface micro-defects is important in order to obtain extended data retention characteristics. By reducing the surface micro-defects to less than 1.2/spl times/10/sup 20//cm/sup 3/, the data retention reliability after 10/sup 6/ to 10/sup 7/ write/erase cycles can be guaranteed for conventional 2-level flash memories, where programmed V/sub t/ is less than 2.4 V.
{"title":"Extended data retention process technology for highly reliable flash EEPROMs of 10/sup 6/ to 10/sup 7/ W/E cycles","authors":"F. Arai, T. Maruyama, R. Shirota","doi":"10.1109/RELPHY.1998.670672","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670672","url":null,"abstract":"Using 16 Mbit flash memories, we clarified the relationship between data retention and Si surface micro-defects just before the tunnel oxidation process. After 10/sup 5/ to 10/sup 6/ write/erase cycles, a small number of singular cells appear to have an anomalously large charge loss rate, when the Si surface defect density due to process damage exceeds 1.2/spl times/10/sup 20//cm/sup 3/. This anomalous charge loss phenomenon strongly depends on the electric field in the tunnel oxide, which is caused by the stored charge in the floating gate. Thus, an accelerated data retention test can be performed by means of the electric field in the tunnel oxide, by controlling the programmed V/sub t/ to be more than 2.4 V just before the retention test (here, neutral V/sub t/ is adjusted to 0 V). By using an accelerated test, it is clarified that controlling the number of surface micro-defects is important in order to obtain extended data retention characteristics. By reducing the surface micro-defects to less than 1.2/spl times/10/sup 20//cm/sup 3/, the data retention reliability after 10/sup 6/ to 10/sup 7/ write/erase cycles can be guaranteed for conventional 2-level flash memories, where programmed V/sub t/ is less than 2.4 V.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132473683","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670667
K. Abe, Yusuke Harada, H. Onoda
The effect of underlayer texture on Cu film properties and electromigration performance in Cu damascene interconnects have been studied. The Cu film orientation depends strongly on the underlayer texture. The Cu<111> orientation can be controlled by changing the preferred orientation of the TiN underlayer, which has the same cubic structure as the Cu. The Cu film deposited on a highly <111>-oriented TiN underlayer indicates a strong <111> orientation. The atomic arrangement between Cu(111) and TiN(111) planes has a rotational angle within /spl plusmn/10/spl deg/ around the <111> axis in spite of lattice mismatch of 14.7%. In the case of damascene interconnects, sidewalls in a trench affect Cu texture and the dependence of the underlayer texture on the Cu film orientation becomes small as line width decreases. EM performance, however, has been improved by the realization of Cu damascene interconnects with a strong <111> orientation.
{"title":"Cu damascene interconnects with crystallographic texture control and its electromigration performance","authors":"K. Abe, Yusuke Harada, H. Onoda","doi":"10.1109/RELPHY.1998.670667","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670667","url":null,"abstract":"The effect of underlayer texture on Cu film properties and electromigration performance in Cu damascene interconnects have been studied. The Cu film orientation depends strongly on the underlayer texture. The Cu<111> orientation can be controlled by changing the preferred orientation of the TiN underlayer, which has the same cubic structure as the Cu. The Cu film deposited on a highly <111>-oriented TiN underlayer indicates a strong <111> orientation. The atomic arrangement between Cu(111) and TiN(111) planes has a rotational angle within /spl plusmn/10/spl deg/ around the <111> axis in spite of lattice mismatch of 14.7%. In the case of damascene interconnects, sidewalls in a trench affect Cu texture and the dependence of the underlayer texture on the Cu film orientation becomes small as line width decreases. EM performance, however, has been improved by the realization of Cu damascene interconnects with a strong <111> orientation.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124524673","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 : 1900-01-01DOI: 10.1109/RELPHY.1998.670436
M. Douglass
The Digital Micromirror Device/sup TM/ (DMD/sup TM/) has made great strides in terms of both performance and reliability. Each device consists of more than 500,000 individually addressable micromirrors. Digital Light Processing/sup TM/ technology, based on the DMD, has been used in such diverse products as projection displays with film-like projected images and photographic-quality printers. Reliability testing of the DMD has demonstrated greater than 100,000 operating hours and more than 1 trillion mirror cycles. This paper discusses DMD reliability development activities, failure modes investigated (e.g. hinge fatigue, hinge memory, stuck mirrors, and environmental robustness), various acceleration techniques (e.g. temperature and duty cycle), corrective actions implemented, and the resulting evidence that the DMD is exceeding original reliability goals.
{"title":"Lifetime estimates and unique failure mechanisms of the Digital Micromirror Device (DMD)","authors":"M. Douglass","doi":"10.1109/RELPHY.1998.670436","DOIUrl":"https://doi.org/10.1109/RELPHY.1998.670436","url":null,"abstract":"The Digital Micromirror Device/sup TM/ (DMD/sup TM/) has made great strides in terms of both performance and reliability. Each device consists of more than 500,000 individually addressable micromirrors. Digital Light Processing/sup TM/ technology, based on the DMD, has been used in such diverse products as projection displays with film-like projected images and photographic-quality printers. Reliability testing of the DMD has demonstrated greater than 100,000 operating hours and more than 1 trillion mirror cycles. This paper discusses DMD reliability development activities, failure modes investigated (e.g. hinge fatigue, hinge memory, stuck mirrors, and environmental robustness), various acceleration techniques (e.g. temperature and duty cycle), corrective actions implemented, and the resulting evidence that the DMD is exceeding original reliability goals.","PeriodicalId":196556,"journal":{"name":"1998 IEEE International Reliability Physics Symposium Proceedings. 36th Annual (Cat. No.98CH36173)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129572147","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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