Pub Date : 2012-05-22DOI: 10.1109/IWCE.2012.6242853
P. Muralidharan, D. Vasileska, P. Wijewarnasuriya
We have developed a computer program that simulates the electrical characteristics of a p+ - n HgCdTe photodetector. Using solutions to the Poisson and Continuity equations we investigate low temperature behavior to determine optimum working conditions to enhance detectivity. Our model considers complete Fermi - Dirac statistics, major recombination mechanisms, band to band tunneling, trap assisted tunneling and impact ionization. Device performance was analyzed as a function of doping and temperature. Simulations show detectivity >; 1011 Jones at 77 K for Hg0.78Cd0.22Te.
我们开发了一个计算机程序来模拟p+ - n HgCdTe光电探测器的电特性。利用泊松方程和连续性方程的解，我们研究了低温行为，以确定最佳工作条件，以提高探测。我们的模型考虑了完整的费米-狄拉克统计、主要的复合机制、带间隧穿、阱辅助隧穿和冲击电离。分析了掺杂和温度对器件性能的影响。模拟结果表明:探测性>;1011琼斯在77 K为Hg0.78Cd0.22Te。
{"title":"Modeling of HgCdTe photodetectors in the LWIR region","authors":"P. Muralidharan, D. Vasileska, P. Wijewarnasuriya","doi":"10.1109/IWCE.2012.6242853","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242853","url":null,"abstract":"We have developed a computer program that simulates the electrical characteristics of a p+ - n HgCdTe photodetector. Using solutions to the Poisson and Continuity equations we investigate low temperature behavior to determine optimum working conditions to enhance detectivity. Our model considers complete Fermi - Dirac statistics, major recombination mechanisms, band to band tunneling, trap assisted tunneling and impact ionization. Device performance was analyzed as a function of doping and temperature. Simulations show detectivity >; 1011 Jones at 77 K for Hg0.78Cd0.22Te.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128743217","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242858
S. Malakooti, E. Hedin, Y. S. Joe
This research deals with molecular electronics of DNA double helices. We consider a 10 base-pair poly(G)-poly(C) double stranded DNA molecule, tilted with respect to the intercontact electric field direction. An advanced tight-binding (TB) model including hopping integrals of the next nearest neighbors (NNN) and DNA helix conformation is implemented. The transport properties, such as single electron transmission spectra and current-voltage characteristics as functions of source-drain voltage and tilt angle, are studied both with and without NNN effects.
{"title":"Molecular electronics of DNA double helices using second-order tight-binding modeling","authors":"S. Malakooti, E. Hedin, Y. S. Joe","doi":"10.1109/IWCE.2012.6242858","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242858","url":null,"abstract":"This research deals with molecular electronics of DNA double helices. We consider a 10 base-pair poly(G)-poly(C) double stranded DNA molecule, tilted with respect to the intercontact electric field direction. An advanced tight-binding (TB) model including hopping integrals of the next nearest neighbors (NNN) and DNA helix conformation is implemented. The transport properties, such as single electron transmission spectra and current-voltage characteristics as functions of source-drain voltage and tilt angle, are studied both with and without NNN effects.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126522318","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242822
M. Aldegunde, A. Martinez
In this paper we study the effect that different phonon scattering mechanisms have on the performance of a silicon gate-all-around nanowire field effect transistor (GAA NWFET). The study is carried out using the Non-equilibrium Green's function (NEGF) formalism in the effective mass approximation. We consider the impact of the bias conditions on the influence of the different phonons on the transport characteristics. We show a quantitative and qualitative difference in the behaviours of the impact of the different phonons for different bias conditions. The simulations including all phonons reproduce the correct behaviour of previous simulations using a sophisticated tight-binding/NEGF approach [1] while presenting a much lower computational effort suitable for technology computer aided design (TCAD) applications. Finally, we confirm that the addition of the phonon related resistivity from simulations including only selected phonons (as proposed in Matthiessen's rule) does not add up to the resistivity of the simulation including all phonons together, underestimating in this way the total phonon related resistivity by 13%.
{"title":"Study of the role of different phonon scattering mechanisms on the performance of a GAA silicon nanowire transistor","authors":"M. Aldegunde, A. Martinez","doi":"10.1109/IWCE.2012.6242822","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242822","url":null,"abstract":"In this paper we study the effect that different phonon scattering mechanisms have on the performance of a silicon gate-all-around nanowire field effect transistor (GAA NWFET). The study is carried out using the Non-equilibrium Green's function (NEGF) formalism in the effective mass approximation. We consider the impact of the bias conditions on the influence of the different phonons on the transport characteristics. We show a quantitative and qualitative difference in the behaviours of the impact of the different phonons for different bias conditions. The simulations including all phonons reproduce the correct behaviour of previous simulations using a sophisticated tight-binding/NEGF approach [1] while presenting a much lower computational effort suitable for technology computer aided design (TCAD) applications. Finally, we confirm that the addition of the phonon related resistivity from simulations including only selected phonons (as proposed in Matthiessen's rule) does not add up to the resistivity of the simulation including all phonons together, underestimating in this way the total phonon related resistivity by 13%.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130355222","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242820
Alfonso Alarcón, V. Nguyen, S. Berrada, Damien Querlioz, J. Saint-Martin, A. Bournel, P. Dollfus
We model the transport behavior of a top-gated graphene field-effect transistor where boron nitride is used as substrate and gate insulator material. Our simulation model is based on the non-equilibrium Green's function approach to solving a tight-binding Hamiltonian for graphene, self-consistently coupled with Poisson's equation. The analysis emphasizes the effects of the chiral character of carriers in graphene in the different transport regimes including Klein and band-to-band tunneling processes. We predict the possible emergence of negative differential conductance and investigate its dependence on the temperature and the BN-induced bandgap. Short-channel effects are evaluated from the analysis of transfer characteristics as a function of gate length and gate insulator thickness. They manifest through the shift of the Dirac point and the appearance of current oscillations at short gate length.
{"title":"Transport behaviors in graphene field effect transistors on boron nitride substrate","authors":"Alfonso Alarcón, V. Nguyen, S. Berrada, Damien Querlioz, J. Saint-Martin, A. Bournel, P. Dollfus","doi":"10.1109/IWCE.2012.6242820","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242820","url":null,"abstract":"We model the transport behavior of a top-gated graphene field-effect transistor where boron nitride is used as substrate and gate insulator material. Our simulation model is based on the non-equilibrium Green's function approach to solving a tight-binding Hamiltonian for graphene, self-consistently coupled with Poisson's equation. The analysis emphasizes the effects of the chiral character of carriers in graphene in the different transport regimes including Klein and band-to-band tunneling processes. We predict the possible emergence of negative differential conductance and investigate its dependence on the temperature and the BN-induced bandgap. Short-channel effects are evaluated from the analysis of transfer characteristics as a function of gate length and gate insulator thickness. They manifest through the shift of the Dirac point and the appearance of current oscillations at short gate length.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115014975","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242838
K. Kalna, J. Ayubi-Moak
A performance of two n-type III-V MOSFET based on an In0.3Ga0.7As channel architecture: a surface channel design with implanted source/drain contacts and a δ-doped, implant-free design, is compared when scaled to gate lengths of 35 nm, 25 nm and 18 nm. The transistor characteristics are simulated using ensemble heterostructure finite element Monte Carlo device simulations assisted by drift-diffusion simulations in a sub-threshold region. The Monte Carlo simulations include a calibrated quantum corrections for each of the scaled transistor and two interface related scattering mechanisms: interface roughness and interface phonons at the interface of polar-polar materials. The scaling of surface channel MOSFETs delivers an increase in the device on-current despite the negative impact of interface phonons, while the implant free MOSFETs scaled to 18 nm gate length suffer substantially from a largely enhanced scattering due to interface roughness and phonons.
{"title":"Monte Carlo simulations of inverse channel versus implant free In0.3Ga0.7As MOSFETs","authors":"K. Kalna, J. Ayubi-Moak","doi":"10.1109/IWCE.2012.6242838","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242838","url":null,"abstract":"A performance of two n-type III-V MOSFET based on an In0.3Ga0.7As channel architecture: a surface channel design with implanted source/drain contacts and a δ-doped, implant-free design, is compared when scaled to gate lengths of 35 nm, 25 nm and 18 nm. The transistor characteristics are simulated using ensemble heterostructure finite element Monte Carlo device simulations assisted by drift-diffusion simulations in a sub-threshold region. The Monte Carlo simulations include a calibrated quantum corrections for each of the scaled transistor and two interface related scattering mechanisms: interface roughness and interface phonons at the interface of polar-polar materials. The scaling of surface channel MOSFETs delivers an increase in the device on-current despite the negative impact of interface phonons, while the implant free MOSFETs scaled to 18 nm gate length suffer substantially from a largely enhanced scattering due to interface roughness and phonons.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"40 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116350496","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242827
J. Cutright, Y. S. Joe, E. Hedin
A nanoscale ring structure, typically referred to as an Aharonov-Bohm (AB) ring, with a quantum dot (QD) embedded in each arm serves a unit cell in a chain-like structure. The transmission through the device is presented as a function of the number of rings in the chain. Zeeman-splitting of the QD energy levels is also modeled and its effects are analyzed. Distinct transmission bands form as the ring number increases. Zeeman splitting causes the number of bands to double, and to cross and diverge as the magnitude of the Zeeman effect increases. I-V plots show a transition from semiconductor characteristics to ohmic properties as the Zeeman splitting approaches the nominal energy value of the QD's.
{"title":"Transmission through multiple nanoscale rings with Zeeman-split quantum dots","authors":"J. Cutright, Y. S. Joe, E. Hedin","doi":"10.1109/IWCE.2012.6242827","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242827","url":null,"abstract":"A nanoscale ring structure, typically referred to as an Aharonov-Bohm (AB) ring, with a quantum dot (QD) embedded in each arm serves a unit cell in a chain-like structure. The transmission through the device is presented as a function of the number of rings in the chain. Zeeman-splitting of the QD energy levels is also modeled and its effects are analyzed. Distinct transmission bands form as the ring number increases. Zeeman splitting causes the number of bands to double, and to cross and diverge as the magnitude of the Zeeman effect increases. I-V plots show a transition from semiconductor characteristics to ohmic properties as the Zeeman splitting approaches the nominal energy value of the QD's.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124742525","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242851
B. Padmanabhan, D. Vasileska, S. Goodnick
Electrical reliability of the AlGaN/GaN material system in both the on and off state regimes is a fundamental problem to be solved before the widespread use of this technology. The two major reliability concerns in this technology is electric field induced strain degradation also known as electromechanical coupling and current collapse mechanism. In the present work, an electro thermal particle based device simulator has been developed to address these two issues. It consists of a Monte Carlo-Poisson solver that is self-consistently coupled with a thermal solver for both the acoustic and the optical phonon baths. This simulator has been used to understand the physics behind these mechanisms that lead to reliability concerns.
{"title":"Reliability of GaN HEMTs: Current degradation in GaN/AlGaN/AlN/GaN HEMT","authors":"B. Padmanabhan, D. Vasileska, S. Goodnick","doi":"10.1109/IWCE.2012.6242851","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242851","url":null,"abstract":"Electrical reliability of the AlGaN/GaN material system in both the on and off state regimes is a fundamental problem to be solved before the widespread use of this technology. The two major reliability concerns in this technology is electric field induced strain degradation also known as electromechanical coupling and current collapse mechanism. In the present work, an electro thermal particle based device simulator has been developed to address these two issues. It consists of a Monte Carlo-Poisson solver that is self-consistently coupled with a thermal solver for both the acoustic and the optical phonon baths. This simulator has been used to understand the physics behind these mechanisms that lead to reliability concerns.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116812032","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242837
X. Ju, M. Becherer, P. Lugli, M. Niemier, W. Porod, G. Csaba
Nanomagnet Logic (NML) is widely considered to be one of the promising for “beyond-CMOS” nanoscale architectures. So far only relatively simple circuits (nanomagnetic logic gates and adders) have been studied experimentally and in simulations. Here we investigate the possibility of building larger-scale computing devices from out-of-plane NML. We designed a systolic pattern matcher circuit that is in principle scalable to arbitrary number of nanomagnets and can match arbitrarily long patterns in an incoming data stream. The design of this systolic architecture for NML makes an important step toward large-scale devices.
{"title":"Design of a systolic pattern matcher for Nanomagnet Logic","authors":"X. Ju, M. Becherer, P. Lugli, M. Niemier, W. Porod, G. Csaba","doi":"10.1109/IWCE.2012.6242837","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242837","url":null,"abstract":"Nanomagnet Logic (NML) is widely considered to be one of the promising for “beyond-CMOS” nanoscale architectures. So far only relatively simple circuits (nanomagnetic logic gates and adders) have been studied experimentally and in simulations. Here we investigate the possibility of building larger-scale computing devices from out-of-plane NML. We designed a systolic pattern matcher circuit that is in principle scalable to arbitrary number of nanomagnets and can match arbitrarily long patterns in an incoming data stream. The design of this systolic architecture for NML makes an important step toward large-scale devices.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114695095","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242839
Jiseok Kim, M. Fischetti, S. Aboud
The electronic and transport properties of sp3-hybridized armchair and zigzag edge silicane nanoribbons have been investigated using nonlocal empirical pseudopotentials and ab-initio calculations. Compared to the armchair graphene nanoribbons, silicane ribbons do no suffer from the chirality dependence of the band gap. Calculated low-field electron mobility and ballistic conductance show a strong edge dependence due to a difference in the effective masses and momentum relaxation rates along the transport direction. Smaller effective masses and momentum relaxation rates in the zigzag edge ribbons results in the electron mobility as much as an order of magnitude larger than the armchair edge ribbons.
{"title":"Electronic and transport properties of armchair and zigzag sp3-hybridized silicane nanoribbons","authors":"Jiseok Kim, M. Fischetti, S. Aboud","doi":"10.1109/IWCE.2012.6242839","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242839","url":null,"abstract":"The electronic and transport properties of sp3-hybridized armchair and zigzag edge silicane nanoribbons have been investigated using nonlocal empirical pseudopotentials and ab-initio calculations. Compared to the armchair graphene nanoribbons, silicane ribbons do no suffer from the chirality dependence of the band gap. Calculated low-field electron mobility and ballistic conductance show a strong edge dependence due to a difference in the effective masses and momentum relaxation rates along the transport direction. Smaller effective masses and momentum relaxation rates in the zigzag edge ribbons results in the electron mobility as much as an order of magnitude larger than the armchair edge ribbons.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"384 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126676521","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 : 2012-05-22DOI: 10.1109/IWCE.2012.6242861
J. Sellier, J. Fonseca, Gerhard Klimeck
Archimedes is the GNU package for Monte Carlo (MC) semiconductor devices simulations. Since its very first release in 2005, users have been able to download the source code under the GNU Public License (GPL). Since then, many features have been introduced in this package, including the ability to perform Archimedes simulation on nanoHUB.org. This paper presents the current code status and anticipated developments.
{"title":"Archimedes, the free Monte Carlo simulator: A GNU package for submicron semiconductor devices on nanoHUB","authors":"J. Sellier, J. Fonseca, Gerhard Klimeck","doi":"10.1109/IWCE.2012.6242861","DOIUrl":"https://doi.org/10.1109/IWCE.2012.6242861","url":null,"abstract":"Archimedes is the GNU package for Monte Carlo (MC) semiconductor devices simulations. Since its very first release in 2005, users have been able to download the source code under the GNU Public License (GPL). Since then, many features have been introduced in this package, including the ability to perform Archimedes simulation on nanoHUB.org. This paper presents the current code status and anticipated developments.","PeriodicalId":375453,"journal":{"name":"2012 15th International Workshop on Computational Electronics","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115962433","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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