Pub Date : 2019-10-17DOI: 10.1109/SISPAD.2019.8870535
K. Vuttivorakulchai, M. Luisier, A. Schenk
The efficiency of converting waste heat to electricity requires a large value of the thermoelectric Figure of merit (ZT). This can be achieved by patterning bulk material into nanostructures like nanowires (NWs). Further improvement results from an increased surface roughness (SR) of such NWs [1]. In this work, Si NWs with stacking faults (SFs) are studied. It is shown that SFs can significantly reduce the lattice thermal conductivity as compared to ideal NWs [2]. A recent derivation of the phonon relaxation time for SF scattering [3] is adapted to the electronic case. It turns out that in most cases the thermoelectric power factor (PF) decreases to a lesser extent than the thermal conductivity. This can double ZT provided that SR scattering of electrons is negligible.
{"title":"Effect of Stacking Faults on the Thermoelectric Figure of Merit of Si Nanowires","authors":"K. Vuttivorakulchai, M. Luisier, A. Schenk","doi":"10.1109/SISPAD.2019.8870535","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870535","url":null,"abstract":"The efficiency of converting waste heat to electricity requires a large value of the thermoelectric Figure of merit (ZT). This can be achieved by patterning bulk material into nanostructures like nanowires (NWs). Further improvement results from an increased surface roughness (SR) of such NWs [1]. In this work, Si NWs with stacking faults (SFs) are studied. It is shown that SFs can significantly reduce the lattice thermal conductivity as compared to ideal NWs [2]. A recent derivation of the phonon relaxation time for SF scattering [3] is adapted to the electronic case. It turns out that in most cases the thermoelectric power factor (PF) decreases to a lesser extent than the thermal conductivity. This can double ZT provided that SR scattering of electrons is negligible.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"34 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85107807","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 : 2019-09-05DOI: 10.1109/SISPAD.2019.8870567
M. Shin, Yucheol Cho, S. Jeon
To accurately assess the effect of trap on the performance of field effect transistors (FETs), atom-level first-principles modeling of channel/oxide/trap and rigorous quantum mechanical transport calculations are necessary. In this work we have developed an innovative approach to solve the challenging problem efficiently. Non-equilibrium Green’s function simulation of InAs FET with a trap in the channel/oxide interface that is atomically modeled by using the density functional theory is demonstrated.
{"title":"Effect of Trap on Carrier Transport in InAs FET with Al2 O3 Oxide: DFT-based NEGF simulations","authors":"M. Shin, Yucheol Cho, S. Jeon","doi":"10.1109/SISPAD.2019.8870567","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870567","url":null,"abstract":"To accurately assess the effect of trap on the performance of field effect transistors (FETs), atom-level first-principles modeling of channel/oxide/trap and rigorous quantum mechanical transport calculations are necessary. In this work we have developed an innovative approach to solve the challenging problem efficiently. Non-equilibrium Green’s function simulation of InAs FET with a trap in the channel/oxide interface that is atomically modeled by using the density functional theory is demonstrated.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"25 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87608004","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 : 2019-09-04DOI: 10.1109/SISPAD.2019.8870555
N. Salles, L. Martin-Samos, Stefano de Gironcoli, L. Giacomazzi, M. Valant, A. Hémeryck, P. Blaise, B. Sklénard, N. Richard
In this paper we study the effect on the electric fields on the formation of bulk Frenkal Pairs and on the migration of oxygen interstitials, IO, and oxygen vacancies, VO, within the framework of Density Functional Theory and Modern Theory of Polarization. At typical OXRRAM field conditions, We show that a significant effect of the electric field is observed only for charged defect. Analyzing the polarization work, we found anomalously high polarization work, for the case of $mathbf{I}_{mathcal{O}}^{-2}$, with respect to the classical picture of the electric work of an isolated point charge. This large difference has to be ascribed to collective contributions coming from the environment.
{"title":"Defect creation and Diffusion under electric fields from first-principles: the prototypical case of silicon dioxide","authors":"N. Salles, L. Martin-Samos, Stefano de Gironcoli, L. Giacomazzi, M. Valant, A. Hémeryck, P. Blaise, B. Sklénard, N. Richard","doi":"10.1109/SISPAD.2019.8870555","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870555","url":null,"abstract":"In this paper we study the effect on the electric fields on the formation of bulk Frenkal Pairs and on the migration of oxygen interstitials, IO, and oxygen vacancies, VO, within the framework of Density Functional Theory and Modern Theory of Polarization. At typical OXRRAM field conditions, We show that a significant effect of the electric field is observed only for charged defect. Analyzing the polarization work, we found anomalously high polarization work, for the case of $mathbf{I}_{mathcal{O}}^{-2}$, with respect to the classical picture of the electric work of an isolated point charge. This large difference has to be ascribed to collective contributions coming from the environment.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"20 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81570611","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 : 2019-09-04DOI: 10.1109/SISPAD.2019.8870382
G. Herrero-Saboya, L. Martin-Samos, A. Hémeryck, D. Rideau, N. Richard
We demonstrate the presence of small Jahn-Teller distortions for interstitial titanium in silicon at different charge states by performing ground state DFT calculations. We prove the existence of three charged transition levels within the band gap by using a non-empirical parameter-free approach, based on the GW approximation, in agreement with DLTS measurements.
{"title":"Electronic and structural properties of interstitial titanium in crystalline silicon from first-principles simulations","authors":"G. Herrero-Saboya, L. Martin-Samos, A. Hémeryck, D. Rideau, N. Richard","doi":"10.1109/SISPAD.2019.8870382","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870382","url":null,"abstract":"We demonstrate the presence of small Jahn-Teller distortions for interstitial titanium in silicon at different charge states by performing ground state DFT calculations. We prove the existence of three charged transition levels within the band gap by using a non-empirical parameter-free approach, based on the GW approximation, in agreement with DLTS measurements.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"16 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88769518","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 : 2019-09-04DOI: 10.1109/sispad.2019.8870416
H. Lee, Junbeom Seo, M. Shin
We present a full quantum transport study of the zero-temperature coefficient (ZTC) point for sub-10 nm gateall-around nanowire p-type field effect transistors (GAA NW pFETs). The phonon scattering effects are included through the self-consistent Born approximation in the non-equilibrium Green’s function framework. The main findings are that the ZTC point can be present in GAA NW pFETs in sub-10 nm regime and the gate voltage at the ZTC point shows an opposite trend and has an upper limit at a certain gate length. This is due to the interplay between the ballisticity ratio and the ballistic current ratio, which can be explained only by the quantum transport simulations.
{"title":"Quantum Transport Simulations of the Zero Temperature Coefficient in Gate-all-around Nanowire pFETs","authors":"H. Lee, Junbeom Seo, M. Shin","doi":"10.1109/sispad.2019.8870416","DOIUrl":"https://doi.org/10.1109/sispad.2019.8870416","url":null,"abstract":"We present a full quantum transport study of the zero-temperature coefficient (ZTC) point for sub-10 nm gateall-around nanowire p-type field effect transistors (GAA NW pFETs). The phonon scattering effects are included through the self-consistent Born approximation in the non-equilibrium Green’s function framework. The main findings are that the ZTC point can be present in GAA NW pFETs in sub-10 nm regime and the gate voltage at the ZTC point shows an opposite trend and has an upper limit at a certain gate length. This is due to the interplay between the ballisticity ratio and the ballistic current ratio, which can be explained only by the quantum transport simulations.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"50 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86892494","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 : 2019-09-01DOI: 10.1109/SISPAD.2019.8870557
D. Rossi, M. Auf der Maur, A. Di Carlo
We present a generalized multi-particle drift-diffusion model capable to overcome the limitations imposed by the classic drift-diffusion model. It was designed as flexible and reusable tool that takes into account explicitly multiple carrier populations, whether charged and neutral, allowing to consider also e.g. exciton transport or ionic motion, crucial for a relevant number of device structures.
{"title":"A generalized multi-particle drift-diffusion simulator for optoelectronic devices","authors":"D. Rossi, M. Auf der Maur, A. Di Carlo","doi":"10.1109/SISPAD.2019.8870557","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870557","url":null,"abstract":"We present a generalized multi-particle drift-diffusion model capable to overcome the limitations imposed by the classic drift-diffusion model. It was designed as flexible and reusable tool that takes into account explicitly multiple carrier populations, whether charged and neutral, allowing to consider also e.g. exciton transport or ionic motion, crucial for a relevant number of device structures.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"143 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73017157","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 : 2019-09-01DOI: 10.1109/SISPAD.2019.8870539
K. Muthuseenu, E. C. Hylin, H. Barnaby, P. Apsangi, M. Kozicki, G. Schlenvogt, Mark A. Townsend
A model for Ag-GeSe3-Ni Conductive Bridge Random Access Memory (CBRAM) device is developed using Technology Computer-Aided Design (TCAD) simulations. A new field-dependent ion mobility saturation model that combines Mott-Gurney ionic transport and a high-field saturation ionic drift velocity model is implemented. Also, an electron mobility model for charge transport through the conductive filament is presented. The model simulates forming and dissolving of the filament at different bias conditions. The simulation results of CBRAM I-V hysteresis curves match well to the experimental data.
{"title":"TCAD Model for Ag-GeSe3-Ni CBRAM Devices","authors":"K. Muthuseenu, E. C. Hylin, H. Barnaby, P. Apsangi, M. Kozicki, G. Schlenvogt, Mark A. Townsend","doi":"10.1109/SISPAD.2019.8870539","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870539","url":null,"abstract":"A model for Ag-GeSe3-Ni Conductive Bridge Random Access Memory (CBRAM) device is developed using Technology Computer-Aided Design (TCAD) simulations. A new field-dependent ion mobility saturation model that combines Mott-Gurney ionic transport and a high-field saturation ionic drift velocity model is implemented. Also, an electron mobility model for charge transport through the conductive filament is presented. The model simulates forming and dissolving of the filament at different bias conditions. The simulation results of CBRAM I-V hysteresis curves match well to the experimental data.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"451 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82972604","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 : 2019-09-01DOI: 10.1109/SISPAD.2019.8870524
S. Bhagdikar, S. Mahapatra
A stochastic framework is presented to model hole trapping and detrapping into and out of individual defects that are present in the gate dielectric of a p-channel MOS transistor. The model calculates thermionic reactions between uncharged and charged states of a defect that are separated by an energy barrier, by using the Gillespie Stochastic Simulation Algorithm (GSSA). The model is validated using experimental data from small area devices under Negative Bias Temperature Instability (NBTI), Random Telegraph Noise (RTN) and Time Dependent Defect Spectroscopy (TDDS) studies.
{"title":"A Stochastic Hole Trapping-Detrapping Framework for NBTI, TDDS and RTN","authors":"S. Bhagdikar, S. Mahapatra","doi":"10.1109/SISPAD.2019.8870524","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870524","url":null,"abstract":"A stochastic framework is presented to model hole trapping and detrapping into and out of individual defects that are present in the gate dielectric of a p-channel MOS transistor. The model calculates thermionic reactions between uncharged and charged states of a defect that are separated by an energy barrier, by using the Gillespie Stochastic Simulation Algorithm (GSSA). The model is validated using experimental data from small area devices under Negative Bias Temperature Instability (NBTI), Random Telegraph Noise (RTN) and Time Dependent Defect Spectroscopy (TDDS) studies.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76771661","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 : 2019-09-01DOI: 10.1109/SISPAD.2019.8870443
A. Toifl, Michael Quell, A. Hössinger, A. Babayan, S. Selberherr, J. Weinbub
We propose a novel dissipation scheme for level-set based wet etching simulations. The scheme enables modeling of the temporal evolution of the etch profile during anisotropic wet etching processes and is based on the local geometry and the crystallographic direction-dependent etch rate. We implemented the scheme into Silvaco’s Victory Process simulator which is utilized in this work to simulate the fabrication of source/drain cavities for sub-28 nm strained metal-oxide-semiconductor fieldeffect transistors. Our results show excellent agreement with experimental data. In particular, the main cavity-related design variables are accurately predicted.
{"title":"Novel Numerical Dissipation Scheme for Level-Set Based Anisotropic Etching Simulations","authors":"A. Toifl, Michael Quell, A. Hössinger, A. Babayan, S. Selberherr, J. Weinbub","doi":"10.1109/SISPAD.2019.8870443","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870443","url":null,"abstract":"We propose a novel dissipation scheme for level-set based wet etching simulations. The scheme enables modeling of the temporal evolution of the etch profile during anisotropic wet etching processes and is based on the local geometry and the crystallographic direction-dependent etch rate. We implemented the scheme into Silvaco’s Victory Process simulator which is utilized in this work to simulate the fabrication of source/drain cavities for sub-28 nm strained metal-oxide-semiconductor fieldeffect transistors. Our results show excellent agreement with experimental data. In particular, the main cavity-related design variables are accurately predicted.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"53 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80742139","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 : 2019-09-01DOI: 10.1109/SISPAD.2019.8870527
S. Kumashiro, Tatsuya Kamei, A. Hiroki, K. Kobayashi
Dominant time constant analysis reveals that the semiconductor equations at hard breakdown turn into a positive feedback state where the convergence of steady state (DC) Newton iteration is substantially difficult even if continuation method is used. A robust simulation method for hard breakdown which detects the appearance of negative time constant during DC Newton iteration and then switches to transient (TR) simulation is proposed. The negative time constant value during the TR simulation is used for the time step restriction and the maximum time constant value is used for the determination of the final time of the TR simulation. By using the proposed method, a trace of the stable operation points in the snapback I-V trajectory corresponding to each DC bias can be obtained robustly with a simple voltage sweep at the voltage boundary.
{"title":"A Robust Simulation Method for Breakdown with Voltage Boundary Condition Utilizing Negative Time Constant Information","authors":"S. Kumashiro, Tatsuya Kamei, A. Hiroki, K. Kobayashi","doi":"10.1109/SISPAD.2019.8870527","DOIUrl":"https://doi.org/10.1109/SISPAD.2019.8870527","url":null,"abstract":"Dominant time constant analysis reveals that the semiconductor equations at hard breakdown turn into a positive feedback state where the convergence of steady state (DC) Newton iteration is substantially difficult even if continuation method is used. A robust simulation method for hard breakdown which detects the appearance of negative time constant during DC Newton iteration and then switches to transient (TR) simulation is proposed. The negative time constant value during the TR simulation is used for the time step restriction and the maximum time constant value is used for the determination of the final time of the TR simulation. By using the proposed method, a trace of the stable operation points in the snapback I-V trajectory corresponding to each DC bias can be obtained robustly with a simple voltage sweep at the voltage boundary.","PeriodicalId":6755,"journal":{"name":"2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88770939","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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