Pub Date : 1993-08-02DOI: 10.1109/CORNEL.1993.303119
R. Mills, G. Dunn, A. Walker, M. Daniels, P. Bishop, K. O. Jensen, B. Ridley, D. Herbert, J. Jefferson
An theoretical study has been made of electron transport over a wide AlGaAs barrier with graded interfaces between GaAs contact layers doped at 1/spl times/10/sup 18/ cm/sup -3/. Drift diffusion theory has been used giving excellent agreement with experimental current-voltage curves over the temperature range 100-200 K. We also present a fully self consistent 1-D Monte Carlo simulation in which the change in alloy composition in the graded interfaces is accounted for by position dependent scattering. We present a method used in the Monte Carlo simulation which allowed the modelling of the heavily doped contact regions even though the electron density could change by up to 8 orders of magnitude in the device.<>
{"title":"Monte Carlo simulation of wide AlGaAs barriers","authors":"R. Mills, G. Dunn, A. Walker, M. Daniels, P. Bishop, K. O. Jensen, B. Ridley, D. Herbert, J. Jefferson","doi":"10.1109/CORNEL.1993.303119","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303119","url":null,"abstract":"An theoretical study has been made of electron transport over a wide AlGaAs barrier with graded interfaces between GaAs contact layers doped at 1/spl times/10/sup 18/ cm/sup -3/. Drift diffusion theory has been used giving excellent agreement with experimental current-voltage curves over the temperature range 100-200 K. We also present a fully self consistent 1-D Monte Carlo simulation in which the change in alloy composition in the graded interfaces is accounted for by position dependent scattering. We present a method used in the Monte Carlo simulation which allowed the modelling of the heavily doped contact regions even though the electron density could change by up to 8 orders of magnitude in the device.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"250 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114831056","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303100
S. Luryi
The author has discussed coherent base propagation effects that can be obtained in stepwise graded and linearly graded bandgap base structures of heterostructure bipolar transistors. These effects open up one or several bands of frequencies above f/sub T/, where the transistor is active. Physically, the active behavior of a coherent transistor results from the phaseshift between the collector current and voltage, acquired during the minority-carrier transit across the base.<>
{"title":"Ultrafast operation of heterostructure bipolar transistors resulting from coherent base transport of minority carriers","authors":"S. Luryi","doi":"10.1109/CORNEL.1993.303100","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303100","url":null,"abstract":"The author has discussed coherent base propagation effects that can be obtained in stepwise graded and linearly graded bandgap base structures of heterostructure bipolar transistors. These effects open up one or several bands of frequencies above f/sub T/, where the transistor is active. Physically, the active behavior of a coherent transistor results from the phaseshift between the collector current and voltage, acquired during the minority-carrier transit across the base.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130336113","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303071
D. Pehlke, D. Pavlidis
A new analytic formalism describing the frequency dependence of current gain and power gain of HBTs based on the T-Model equivalent circuit is presented. It is found that while extrapolation serves as a conservative benchmark for HBT high-speed device comparison, it often significantly underestimates the actual intercept frequency for f/sub T/, with an experimental example presented here with error of 50%. The frequency dependence of G/sub MAX/ shows it to be unsuitable for extrapolation to find f/sub MAX/, while extrapolation of Unilateral Gain (U) will generally in the absence of resonances yield accurate values for f/sub MAX/. The conditions for resonance and resonance frequencies for U are analytically investigated here, and new analytic expressions are developed and experimentally demonstrated for highly accurate determination of the f/sub T/ and f/sub MAX/ intercept frequencies of HBTs.<>
{"title":"New analytic determination of f/sub T/, f/sub MAX/ and the frequency dependence of current gain and power gain in HBTs","authors":"D. Pehlke, D. Pavlidis","doi":"10.1109/CORNEL.1993.303071","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303071","url":null,"abstract":"A new analytic formalism describing the frequency dependence of current gain and power gain of HBTs based on the T-Model equivalent circuit is presented. It is found that while extrapolation serves as a conservative benchmark for HBT high-speed device comparison, it often significantly underestimates the actual intercept frequency for f/sub T/, with an experimental example presented here with error of 50%. The frequency dependence of G/sub MAX/ shows it to be unsuitable for extrapolation to find f/sub MAX/, while extrapolation of Unilateral Gain (U) will generally in the absence of resonances yield accurate values for f/sub MAX/. The conditions for resonance and resonance frequencies for U are analytically investigated here, and new analytic expressions are developed and experimentally demonstrated for highly accurate determination of the f/sub T/ and f/sub MAX/ intercept frequencies of HBTs.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124803055","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303089
A. Caddemi, G. Martines, M. Sannino
A method for the complete characterization of microwave transistors in terms of noise, gain and scattering parameters using a computer-controlled noise figure measuring set-up only is presented. A modeling procedure exploiting both scattering and noise parameters has been employed to extract the equivalent circuit which gives the best fit of the experimental data. Results are reported concerning the complete characterization and modeling of a series of ten pseudomorphic HEMTs in the 8-16 GHz range.<>
{"title":"Statistical modeling of pseudomorphic HEMTs from automated noise and scattering parameter measurements","authors":"A. Caddemi, G. Martines, M. Sannino","doi":"10.1109/CORNEL.1993.303089","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303089","url":null,"abstract":"A method for the complete characterization of microwave transistors in terms of noise, gain and scattering parameters using a computer-controlled noise figure measuring set-up only is presented. A modeling procedure exploiting both scattering and noise parameters has been employed to extract the equivalent circuit which gives the best fit of the experimental data. Results are reported concerning the complete characterization and modeling of a series of ten pseudomorphic HEMTs in the 8-16 GHz range.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128047573","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303112
M. Leary, J. Ballantyne
The authors describe the design of two MSM waveguide photodetectors which share their layer structure with high electron mobility transistors. This design makes these detectors particularly suited to integration with HEMTs in OEIC's. Resistive loss at the electrode surface, radiation loss into the substrate, and scattering loss are all accounted for in the optimization for internal detection efficiency of these 50 GHz detectors.<>
{"title":"MSM waveguide photodetectors optimized for monolithic integration with HEMTs","authors":"M. Leary, J. Ballantyne","doi":"10.1109/CORNEL.1993.303112","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303112","url":null,"abstract":"The authors describe the design of two MSM waveguide photodetectors which share their layer structure with high electron mobility transistors. This design makes these detectors particularly suited to integration with HEMTs in OEIC's. Resistive loss at the electrode surface, radiation loss into the substrate, and scattering loss are all accounted for in the optimization for internal detection efficiency of these 50 GHz detectors.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131652895","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303104
R. Kamoua, H. Eisele, George I. Haddad, G. Munns, M. Sherwin
The potential of InP Gunn devices as power sources in the fundamental mode at D-band frequencies (110 GHz-170 GHz) is investigated. A self-consistent ensemble Monte Carte model has been developed to design and identify suitable structures for operation in this frequency range. Using this model with typical InP material parameters found in the literature, it is shown to give results inconsistent with experiment. Based on experimental results from a 1.7 /spl mu/m long Gunn structure, more realistic material parameters were estimated. The resulting model is then used to design various structures with active regions in the 1 /spl mu/m range. In particular, two structures, one with a flat doping profile and the other with a linearly graded doping profile, were fabricated and tested. State-of-the-art performance from these structures operating in the fundamental mode was obtained at frequencies ranging from 108.3 GHz to 155 GHz. The flat structure yielded optimum results at 108.3 GHz with a power level of 33 mW while the graded structure gave 20 mW at 120 GHz, 17 mW at 133 GHz, 10 mW at 136 GHz, and 8 mW at 155 GHz. These results are compared with the model predictions.<>
{"title":"Development of an appropriate model for the design of D-band InP Gunn devices","authors":"R. Kamoua, H. Eisele, George I. Haddad, G. Munns, M. Sherwin","doi":"10.1109/CORNEL.1993.303104","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303104","url":null,"abstract":"The potential of InP Gunn devices as power sources in the fundamental mode at D-band frequencies (110 GHz-170 GHz) is investigated. A self-consistent ensemble Monte Carte model has been developed to design and identify suitable structures for operation in this frequency range. Using this model with typical InP material parameters found in the literature, it is shown to give results inconsistent with experiment. Based on experimental results from a 1.7 /spl mu/m long Gunn structure, more realistic material parameters were estimated. The resulting model is then used to design various structures with active regions in the 1 /spl mu/m range. In particular, two structures, one with a flat doping profile and the other with a linearly graded doping profile, were fabricated and tested. State-of-the-art performance from these structures operating in the fundamental mode was obtained at frequencies ranging from 108.3 GHz to 155 GHz. The flat structure yielded optimum results at 108.3 GHz with a power level of 33 mW while the graded structure gave 20 mW at 120 GHz, 17 mW at 133 GHz, 10 mW at 136 GHz, and 8 mW at 155 GHz. These results are compared with the model predictions.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114577618","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303129
J. Shealy, M. Hashemi, S. Denbaars, U. Mishra, T.K. Liu, J.J. Brown, M. Lui
We present a technology to increase both the two-terminal gate-drain breakdown and subsequently the three-terminal-off-state breakdown of AlInAs/GaInAs HEMTs to record values without substantial impact on other parameters such as Idss and g/sub m/. The breakdown in these structures is dependent on the injection of electrons from the source (channel current) and the gate (gate leakage) into the channel where multiplication occurs (due to high electric fields at the drain), producing holes which are swept back into the gate and source electrodes. These phenomena can be suppressed by increasing the gate barrier height and alleviating the fields at the drain. In our approach we have achieved both by incorporating a p+-2DEG junction as the gate which modulates the 2DEG gas and by utilizing selective regrowth of the source and drain regions by MOCVD. The 1 /spl mu/m gate length devices fabricated show a full channel current of 350 mA/mm, transconductance of 240 mS/mm and record high two-terminal gate-drain and three-terminal-off-state breakdown voltages of 31 V and 28 V, respectively. The gate-to-drain spacing is 1/spl mu/m and the breakdown is defined at 1mA/mm gate leakage. Further, temperature measurements were made to characterize both two-terminal and three-terminal-on-state breakdown. The gate current behavior is presented along with a calculated ionization rate which is compared with rates previously reported.<>
{"title":"Breakdown characterization of AlInAs/GaInAs junction modulated HEMTs (JHEMTs) with regrown ohmic contacts by MOCVD","authors":"J. Shealy, M. Hashemi, S. Denbaars, U. Mishra, T.K. Liu, J.J. Brown, M. Lui","doi":"10.1109/CORNEL.1993.303129","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303129","url":null,"abstract":"We present a technology to increase both the two-terminal gate-drain breakdown and subsequently the three-terminal-off-state breakdown of AlInAs/GaInAs HEMTs to record values without substantial impact on other parameters such as Idss and g/sub m/. The breakdown in these structures is dependent on the injection of electrons from the source (channel current) and the gate (gate leakage) into the channel where multiplication occurs (due to high electric fields at the drain), producing holes which are swept back into the gate and source electrodes. These phenomena can be suppressed by increasing the gate barrier height and alleviating the fields at the drain. In our approach we have achieved both by incorporating a p+-2DEG junction as the gate which modulates the 2DEG gas and by utilizing selective regrowth of the source and drain regions by MOCVD. The 1 /spl mu/m gate length devices fabricated show a full channel current of 350 mA/mm, transconductance of 240 mS/mm and record high two-terminal gate-drain and three-terminal-off-state breakdown voltages of 31 V and 28 V, respectively. The gate-to-drain spacing is 1/spl mu/m and the breakdown is defined at 1mA/mm gate leakage. Further, temperature measurements were made to characterize both two-terminal and three-terminal-on-state breakdown. The gate current behavior is presented along with a calculated ionization rate which is compared with rates previously reported.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123837006","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303114
T. Winslow, A. Morris, R. Trew
A gate breakdown model for MESFETs is presented. The model is based on quantum tunneling initiated avalanche ionization. The breakdown model is incorporated into a physics based MESFET model. Forward and reverse gate conduction an shown to be the main factors in determining the power and efficiency of MESFET amplifiers.<>
{"title":"An improved gate breakdown model for studying high efficiency MESFET operation","authors":"T. Winslow, A. Morris, R. Trew","doi":"10.1109/CORNEL.1993.303114","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303114","url":null,"abstract":"A gate breakdown model for MESFETs is presented. The model is based on quantum tunneling initiated avalanche ionization. The breakdown model is incorporated into a physics based MESFET model. Forward and reverse gate conduction an shown to be the main factors in determining the power and efficiency of MESFET amplifiers.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121189839","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303126
M. Matloubian, L. Larson, A. Brown, L. Jelloian, L. Nguyen, M. Lui, T. Liu, J. Brown, M. Thompson, W. Lam, A. Kurdoghlian, R. Rhodes, M. Delaney, J. Pence
The authors have conducted a systematic effort to improve the breakdown voltage of InP-based HEMTs without compromising their high frequency performance, and have demonstrated millimeter wave circuit results that are comparable to or exceed those of the best GaAs-based PHEMTs in the critical area of power-added efficiency and output power. This improvement was accomplished by a combination of developments in material growth and device design and fabrication.<>
{"title":"InP-based HEMTs for the realization of ultra-high efficiency millimeter wave power amplifiers","authors":"M. Matloubian, L. Larson, A. Brown, L. Jelloian, L. Nguyen, M. Lui, T. Liu, J. Brown, M. Thompson, W. Lam, A. Kurdoghlian, R. Rhodes, M. Delaney, J. Pence","doi":"10.1109/CORNEL.1993.303126","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303126","url":null,"abstract":"The authors have conducted a systematic effort to improve the breakdown voltage of InP-based HEMTs without compromising their high frequency performance, and have demonstrated millimeter wave circuit results that are comparable to or exceed those of the best GaAs-based PHEMTs in the critical area of power-added efficiency and output power. This improvement was accomplished by a combination of developments in material growth and device design and fabrication.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125905773","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 : 1993-08-02DOI: 10.1109/CORNEL.1993.303113
J. Sheridan, B. Nechay, D. Bloom, P. Solomon, Y. Pao
We report the fabrication of a 1 /spl mu/m photoconductive gap voltage step generator with constant output voltage of 0.10 V for 100 ps and a 2 ps rise time. The photoconductor is fabricated on GaAs/AlGaAs MODFET material and uses the two-dimensional electron gas in the FET channel as the conductive medium. It is fully process-compatible with MODFETs. In devices with standard ohmic contacts, the output current stayed constant for up to 50 ps, even though the electric field in the gap is expected to collapse in less than 1 ps. Two-dimensional device simulations show that, although the field in the gap does collapse on the expected time scale, the current is initially determined by the contacts. A new photoconductor design, in which the ohmic contacts are laterally recessed from the etched gap region, further delayed field collapse, extending constant voltage operation to 100 ps.<>
{"title":"Delay of field collapse in photoconductive gaps fabricated on GaAs/AlGaAs MODFET material","authors":"J. Sheridan, B. Nechay, D. Bloom, P. Solomon, Y. Pao","doi":"10.1109/CORNEL.1993.303113","DOIUrl":"https://doi.org/10.1109/CORNEL.1993.303113","url":null,"abstract":"We report the fabrication of a 1 /spl mu/m photoconductive gap voltage step generator with constant output voltage of 0.10 V for 100 ps and a 2 ps rise time. The photoconductor is fabricated on GaAs/AlGaAs MODFET material and uses the two-dimensional electron gas in the FET channel as the conductive medium. It is fully process-compatible with MODFETs. In devices with standard ohmic contacts, the output current stayed constant for up to 50 ps, even though the electric field in the gap is expected to collapse in less than 1 ps. Two-dimensional device simulations show that, although the field in the gap does collapse on the expected time scale, the current is initially determined by the contacts. A new photoconductor design, in which the ohmic contacts are laterally recessed from the etched gap region, further delayed field collapse, extending constant voltage operation to 100 ps.<<ETX>>","PeriodicalId":129440,"journal":{"name":"Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130265102","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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