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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Magnus, W.; Collaert, N.; Mocuta, A.; Groeseneken, G.
Title Self-consistent procedure including envelope function normalization for full-zone Schrodinger-Poisson problems with transmitting boundary conditions Type A1 Journal article
Year (down) 2018 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 124 Issue 20 Pages 204501
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In the quantum mechanical simulation of exploratory semiconductor devices, continuum methods based on a k.p/envelope function model have the potential to significantly reduce the computational burden compared to prevalent atomistic methods. However, full-zone k.p/envelope function simulation approaches are scarce and existing implementations are not self-consistent with the calculation of the electrostatic potential due to the lack of a stable procedure and a proper normalization of the multi-band envelope functions. Here, we therefore present a self-consistent procedure based on a full-zone spectral k.p/envelope function band structure model. First, we develop a proper normalization for the multi-band envelope functions in the presence of transmitting boundary conditions. This enables the calculation of the free carrier densities. Next, we construct a procedure to obtain self-consistency of the carrier densities with the electrostatic potential. This procedure is stabilized with an adaptive scheme that relies on the solution of Poisson's equation in the Gummel form, combined with successive underrelaxation. Finally, we apply our procedure to homostructure In0.53Ga0.47As tunnel field-effect transistors (TFETs) and staggered heterostructure GaAs0.5Sb0.5/In0.53Ga0.47As TFETs and show the importance of self-consistency on the device predictions for scaled dimensions. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000451743900015 Publication Date 2018-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 1 Open Access
Notes ; This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 2.068
Call Number UA @ admin @ c:irua:156291 Serial 5228
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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Magnus, W.; Collaert, N.; Mocuta, A.; Groeseneken, G.
Title Self-consistent 30-band simulation approach for (non-)uniformly strained confined heterostructure tunnel field-effect transistors Type P1 Proceeding
Year (down) 2017 Publication Simulation of Semiconductor Processes and, Devices (SISPAD)AND DEVICES (SISPAD 2017) Abbreviated Journal
Volume Issue Pages 29-32
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract Heterostructures of III-V materials under a mechanical strain are being actively researched to enhance the performance of the tunnel field-effect transistor (TFET). In scaled III-V device structures, however, the interplay between the effects of strain and quantum confinement on the semiconductor band structure and hence the performance is highly non-trivial. We have therefore developed a computationally efficient quantum mechanical simulator Pharos, which enables self-consistent full-zone k.p-based simulations of III-V TFETs under a general non-uniform strain. We present the self-consistent procedure and demonstrate it on confined staggered bandgap GaAs0.5Sb0.5/In0.53Ga0.47As TFETs. We find a large performance degradation due to size-induced quantum confinement compared to non-confined devices. We show that some performance can be regained either by applying a uniform biaxial tensile strain or through the non-uniform strain profile at a lattice-mismatched heterostructure.
Address
Corporate Author Thesis
Publisher Ieee Place of Publication New york Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-4-86348-610-2 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:149949 Serial 4978
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Author Mohammed, M.; Verhulst, A.S.; Verreck, D.; Van de Put, M.; Simoen, E.; Sorée, B.; Kaczer, B.; Degraeve, R.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
Title Electric-field induced quantum broadening of the characteristic energy level of traps in semiconductors and oxides Type A1 Journal article
Year (down) 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 120 Issue 120 Pages 245704
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The trap-assisted tunneling (TAT) current in tunnel field-effect transistors (TFETs) is one of the crucial factors degrading the sub-60 mV/dec sub-threshold swing. To correctly predict the TAT currents, an accurate description of the trap is required. Since electric fields in TFETs typically reach beyond 10(6) V/cm, there is a need to quantify the impact of such high field on the traps. We use a quantum mechanical implementation based on the modified transfer matrix method to obtain the trap energy level. We present the qualitative impact of electric field on different trap configurations, locations, and host materials, including both semiconductors and oxides. We determine that there is an electric-field related trap level shift and level broadening. We find that these electric-field induced quantum effects can enhance the trap emission rates. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000392174000028 Publication Date 2016-12-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 6 Open Access
Notes ; This work was supported by imec's Industrial Affiliation Program. D. Verreck acknowledges the support of a PhD stipend from IWT-Vlaanderen. ; Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:141481 Serial 4593
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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Uniform strain in heterostructure tunnel field-effect transistors Type A1 Journal article
Year (down) 2016 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 37 Issue 37 Pages 337-340
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Strain can strongly impact the performance of III-V tunnel field-effect transistors (TFETs). However, previous studies on homostructure TFETs have found an increase in ON-current to be accompanied with a degradation of subthreshold swing. We perform 30-band quantum mechanical simulations of staggered heterostructure p-n-i-n TFETs submitted to uniaxial and biaxial uniform stress and find the origin of the subthreshold degradation to be a reduction of the density of states in the strained case. We apply an alternative configuration including a lowly doped pocket in the source, which allows to take full benefit of the strain-induced increase in ON-current.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000372372100026 Publication Date 2016-01-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.048 Times cited 17 Open Access
Notes ; This work was supported by the imec Industrial Affiliation Program. The work of D. Verreck was supported by the Agency for Innovation by Science and Technology in Flanders. The review of this letter was arranged by Editor Z. Chen. ; Approved Most recent IF: 3.048
Call Number UA @ lucian @ c:irua:133207 Serial 4271
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Author Verreck, D.; Verhulst, A.S.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Non-uniform strain in lattice-mismatched heterostructure tunnel field-effect transistors Type P1 Proceeding
Year (down) 2016 Publication Solid-State Device Research (ESSDERC), European Conference T2 – 46th European Solid-State Device Research Conference (ESSDERC) / 42nd, European Solid-State Circuits Conference (ESSCIRC), SEP 12-15, 2016, Lausanne, SWITZERLAND Abbreviated Journal
Volume Issue Pages 412-415
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract Because of its localized impact on the band structure, non-uniform strain at the heterojunction between lattice-mismatched materials has the potential to significantly enlarge the design space for tunnel-field effect transistors (TFET). However, the impact of a complex strain profile on TFET performance is difficult to predict. We have therefore developed a 2D quantum mechanical transport formalism capable of simulating the effects of a general non-uniform strain. We demonstrate the formalism for the GaAsxSb(1-x)/InyGa(1-y) As system and show that a performance improvement over a lattice-matched reference is indeed possible, allowing for relaxed requirements on the source doping. We also point out that the added design parameter of mismatch is not free, but limited by the desired effective bandgap at the tunnel junction.
Address
Corporate Author Thesis
Publisher Ieee Place of Publication New york Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-5090-2969-3 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:138233 Serial 4358
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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.; Sorée, B.; Magnus, W.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
Title Full-zone spectral envelope function formalism for the optimization of line and point tunnel field-effect transistors Type A1 Journal article
Year (down) 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 118 Issue 118 Pages 134502
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Efficient quantum mechanical simulation of tunnel field-effect transistors (TFETs) is indispensable to allow for an optimal configuration identification. We therefore present a full-zone 15-band quantum mechanical solver based on the envelope function formalism and employing a spectral method to reduce computational complexity and handle spurious solutions. We demonstrate the versatility of the solver by simulating a 40 nm wide In0.53Ga0.47As lineTFET and comparing it to p-n-i-n configurations with various pocket and body thicknesses. We find that the lineTFET performance is not degraded compared to semi-classical simulations. Furthermore, we show that a suitably optimized p-n-i-n TFET can obtain similar performance to the lineTFET. (C) 2015 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000362668400025 Publication Date 2015-10-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 9 Open Access
Notes ; D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
Call Number UA @ lucian @ c:irua:128765 Serial 4183
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Author Verreck, D.; Verhulst, A.S.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Improved source design for p-type tunnel field-effect transistors : towards truly complementary logic Type A1 Journal article
Year (down) 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 105 Issue 24 Pages 243506
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Complementary logic based on tunnel field-effect transistors (TFETs) would drastically reduce power consumption thanks to the TFET's potential to obtain a sub-60 mV/dec subthreshold swing (SS). However, p-type TFETs typically do not meet the performance of n-TFETs for direct bandgap III-V configurations. The p-TFET SS stays well above 60 mV/dec, due to the low density of states in the conduction band. We therefore propose a source configuration in which a highly doped region is maintained only near the tunnel junction. In the remaining part of the source, the hot carriers in the exponential tail of the Fermi-Dirac distribution are blocked by reducing the doping degeneracy, either with a source section with a lower doping concentration or with a heterostructure. We apply this concept to n-p-i-p configurations consisting of In0.53Ga0.47As and an InP-InAs heterostructure. 15-band quantum mechanical simulations predict that the configurations with our source design can obtain sub-60 mV/dec SS, with an on-current comparable to the conventional source design. (C) 2014 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000346643600076 Publication Date 2014-12-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 10 Open Access
Notes ; D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 3.411; 2014 IF: 3.302
Call Number UA @ lucian @ c:irua:122798 Serial 1568
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Author Toledano-Luque, M.; Matagne, P.; Sibaja-Hernandez, A.; Chiarella, T.; Ragnarsson, L.-A.; Sorée, B.; Cho, M.; Mocuta, A.; Thean, A.
Title Superior reliability of junctionless pFinFETs by reduced oxide electric field Type A1 Journal article
Year (down) 2014 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 35 Issue 12 Pages 1179-1181
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Superior reliability of junctionless (JL) compared with inversion-mode field-effect transistors (FETs) is experimentally demonstrated on bulk FinFET wafers. The reduced negative bias temperature instability (NBTI) of JL pFETs outperforms the previously reported best NBTI reliability data obtained with Si channel devices and guarantees 10-year lifetime at typical operating voltages and high temperature. This behavior is understood through the reduced oxide electric field and lessened interaction between charge carriers and oxide traps during device operation. These findings encourage the investigation of JL devices with alternative channels as a promising alternative for 7-nm technology nodes meeting reliability targets.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000345575400006 Publication Date 2014-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106;1558-0563; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.048 Times cited 13 Open Access
Notes ; This work was supported by the imec's Core Partner Program. The review of this letter was arranged by Editor J. Schmitz. ; Approved Most recent IF: 3.048; 2014 IF: 2.754
Call Number UA @ lucian @ c:irua:122192 Serial 3378
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Author Verhulst, A.S.; Verreck, D.; Smets, Q.; Kao, K.-H.; Van de Put, M.; Rooyackers, R.; Sorée, B.; Vandooren, A.; De Meyer, K.; Groeseneken, G.; Heyns, M.M.; Mocuta, A.; Collaert, N.; Thean, A.V.-Y.
Title Perspective of tunnel-FET for future low-power technology nodes Type P1 Proceeding
Year (down) 2014 Publication 2014 Ieee International Electron Devices Meeting (iedm) Abbreviated Journal
Volume Issue Pages
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Ieee Place of Publication New york Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-4799-8000-0 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:144789 Serial 4679
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