Pub Date : 2014-12-29DOI: 10.1109/ASDAM.2014.6998639
J. Nahlik, Z. Šobáň, J. Voves, V. Jurka, P. Vasek
Graphene is perspective material for future carbon based electronics, flexible electronics and other applications. The necessary condition for the commercial use is the high quality graphene growth and semiconductor technology compatible process of whole field effect transistor (FET). One of suitable method for large scale graphene monolayer preparation is the thermal annealing of semi-insulating SiC substrate. One important task of graphene FET process is reliable, cheap and simple gate structure preparation. In this work we present our results of using MicroChem Lift-Off Resist (LOR) layer as a dielectric layer for SiC graphene FETs. LOR resist is based on polydimethylglutharimide. Its unique properties enable to perform exceptionally well resolution imaging, easy process tuning, high yields and superior deposition line width control. In the case of polymer based dielectric layers the breakdown voltage is important parameter. We prepared two sets of different capacitor structures with LOR dielectric layer and Au/Cr electrodes. The first set exhibits very low breakdown voltages (about 3 V). The optimisation of the LOR layer deposition process in the second set increased the breakdown voltage over 40 V keeping the leakage current lower than 2 nA. The second process with LOR layer was used for the preparation of graphene FETs on SiC substrates. The first measurements show resistivity dependence on gate voltage.
{"title":"SiC graphene FET with polydimethylglutharimide as a gate dielectric layer","authors":"J. Nahlik, Z. Šobáň, J. Voves, V. Jurka, P. Vasek","doi":"10.1109/ASDAM.2014.6998639","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998639","url":null,"abstract":"Graphene is perspective material for future carbon based electronics, flexible electronics and other applications. The necessary condition for the commercial use is the high quality graphene growth and semiconductor technology compatible process of whole field effect transistor (FET). One of suitable method for large scale graphene monolayer preparation is the thermal annealing of semi-insulating SiC substrate. One important task of graphene FET process is reliable, cheap and simple gate structure preparation. In this work we present our results of using MicroChem Lift-Off Resist (LOR) layer as a dielectric layer for SiC graphene FETs. LOR resist is based on polydimethylglutharimide. Its unique properties enable to perform exceptionally well resolution imaging, easy process tuning, high yields and superior deposition line width control. In the case of polymer based dielectric layers the breakdown voltage is important parameter. We prepared two sets of different capacitor structures with LOR dielectric layer and Au/Cr electrodes. The first set exhibits very low breakdown voltages (about 3 V). The optimisation of the LOR layer deposition process in the second set increased the breakdown voltage over 40 V keeping the leakage current lower than 2 nA. The second process with LOR layer was used for the preparation of graphene FETs on SiC substrates. The first measurements show resistivity dependence on gate voltage.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132978933","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998668
S. Faramehr, P. Igić, K. Kalna
The effect of GaN cap and its thickness on device performance is investigated using simulations by Silvaco Atlas toolbox. The simulations are based on meticulous calibration of a conventional, lateral, GaN capped, 1μm gate-length HEMT with a source-to-gate and gate-to-drain spacings of 2μm, and 3μm, respectively. The breakdown voltage of the GaN HEMT is improved by the aid of p-doped GaN cap and field plates to BV=630V showing an improvement of 540V in comparison to an unoptimized device. Furthermore, the possible creation of two dimensional hole gas (2DHG) at the interface of GaN cap and AlGaN barrier and its effect on the device behaviour is studied.
{"title":"Modelling and optimization of GaN capped HEMTs","authors":"S. Faramehr, P. Igić, K. Kalna","doi":"10.1109/ASDAM.2014.6998668","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998668","url":null,"abstract":"The effect of GaN cap and its thickness on device performance is investigated using simulations by Silvaco Atlas toolbox. The simulations are based on meticulous calibration of a conventional, lateral, GaN capped, 1μm gate-length HEMT with a source-to-gate and gate-to-drain spacings of 2μm, and 3μm, respectively. The breakdown voltage of the GaN HEMT is improved by the aid of p-doped GaN cap and field plates to BV=630V showing an improvement of 540V in comparison to an unoptimized device. Furthermore, the possible creation of two dimensional hole gas (2DHG) at the interface of GaN cap and AlGaN barrier and its effect on the device behaviour is studied.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127425506","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998676
A. Kosa, L. Stuchlíková, P. Benko, J. Jakus, L. Harmatha, J. Kováč, B. Ściana, W. Dawidowski, D. Radziewicz, D. Pucicki, M. Tlaczala
Deep Level Transient Fourier Spectroscopy study of charge carrier emission from quantum wells and electrically active defects in triple quantum well InGaAsN/GaAs heterostructures is discussed. Main attention is focused on the comparison and evaluation of measured spectra and to state the conditions of quantum well charge carrier emission identification. The presence of several deep energy levels and their parameters typical for GaAs are reported.
{"title":"DLTS study of electrically active defects in triple quantum well InGaAsN/GaAs heterostructures","authors":"A. Kosa, L. Stuchlíková, P. Benko, J. Jakus, L. Harmatha, J. Kováč, B. Ściana, W. Dawidowski, D. Radziewicz, D. Pucicki, M. Tlaczala","doi":"10.1109/ASDAM.2014.6998676","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998676","url":null,"abstract":"Deep Level Transient Fourier Spectroscopy study of charge carrier emission from quantum wells and electrically active defects in triple quantum well InGaAsN/GaAs heterostructures is discussed. Main attention is focused on the comparison and evaluation of measured spectra and to state the conditions of quantum well charge carrier emission identification. The presence of several deep energy levels and their parameters typical for GaAs are reported.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114602324","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998702
P. Juhasz, L. Stuchlíková, M. Micjan, L. Harmatha, J. Jakabovic, M. Weis
The defect states are investigated in ITO/P3HT/In organic diode structure by steady-state current-voltage technique and deep-level transient spectroscopy (DLTS) method. The temperature dependencies are used to evaluate charge transport activation energies. The activation energy of about 0.15 eV estimated from the current-voltage measurement as well as from the DLTS technique represents the dominant defect state in P3HT.
{"title":"Determination of defect states in P3HT material for solar cell application","authors":"P. Juhasz, L. Stuchlíková, M. Micjan, L. Harmatha, J. Jakabovic, M. Weis","doi":"10.1109/ASDAM.2014.6998702","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998702","url":null,"abstract":"The defect states are investigated in ITO/P3HT/In organic diode structure by steady-state current-voltage technique and deep-level transient spectroscopy (DLTS) method. The temperature dependencies are used to evaluate charge transport activation energies. The activation energy of about 0.15 eV estimated from the current-voltage measurement as well as from the DLTS technique represents the dominant defect state in P3HT.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128567996","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998694
G. Vanko, M. Vojs, T. Ižák, Š. Potocký, P. Choleva, M. Marton, I. Ryger, J. Dzuba, T. Lalinsky
In this work, we present an application of NCD layers as backside cooling for AlGaN/GaN heterostructures grown on Si substrates. In this case, diamond nucleation is the most limiting technological step due to low mechanical stability of GaN membranes. We observed that standard nucleation techniques (ultrasonic seeding or bias enhanced nucleation) caused cracking of the membranes or not appropriate nucleation efficiency in the Z-depth of structures. Therefore we implemented PVA polymer consisting of diamond powder as seeding composite which resulted in a successful growth of diamond thin film.
{"title":"AlGaN/GaN micromembranes with diamond coating for high electron mobility transistors operated at high temperatures","authors":"G. Vanko, M. Vojs, T. Ižák, Š. Potocký, P. Choleva, M. Marton, I. Ryger, J. Dzuba, T. Lalinsky","doi":"10.1109/ASDAM.2014.6998694","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998694","url":null,"abstract":"In this work, we present an application of NCD layers as backside cooling for AlGaN/GaN heterostructures grown on Si substrates. In this case, diamond nucleation is the most limiting technological step due to low mechanical stability of GaN membranes. We observed that standard nucleation techniques (ultrasonic seeding or bias enhanced nucleation) caused cracking of the membranes or not appropriate nucleation efficiency in the Z-depth of structures. Therefore we implemented PVA polymer consisting of diamond powder as seeding composite which resulted in a successful growth of diamond thin film.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129361517","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998635
M. Weis
Organic semiconductors have been already successfully applied for organic light-emitting diodes (OLEDs) and organic solar cells. Even though these applications already commercially available, the research on organic field-effect transistors (OFETs) is still ongoing to improve them to level required for applications. The aim of this review is to summarize various approaches to OFET devices with horizontal geometry and possible applications.
{"title":"Organic semiconductor based field-effect transistors","authors":"M. Weis","doi":"10.1109/ASDAM.2014.6998635","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998635","url":null,"abstract":"Organic semiconductors have been already successfully applied for organic light-emitting diodes (OLEDs) and organic solar cells. Even though these applications already commercially available, the research on organic field-effect transistors (OFETs) is still ongoing to improve them to level required for applications. The aim of this review is to summarize various approaches to OFET devices with horizontal geometry and possible applications.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129378936","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998670
A. Ionescu
This paper reports on the state-of-the-art and recent advances concerning the tunnelling FETs as energy efficient switches, capable of operating at sub-0.5V due to their low Ioff and steep subthermal subthreshold slope (better than 60mV/decade at room temperature). Overall, it appears that the engineering of heterojunction tunnelling FETs with the application of some technology boosters similar to advanced silicon CMOS can offer the appropriate path for a high performance complementary platform for this new family of devices. More aggressive scaling of their operation voltage, below 0.1V can be achieved with new concepts like the Electron-Hole Bilayer Tunnel FET exploiting the effect of low dimensionality on the Density of States (DOS).
{"title":"Energy efficient computing with tunnel FETs","authors":"A. Ionescu","doi":"10.1109/ASDAM.2014.6998670","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998670","url":null,"abstract":"This paper reports on the state-of-the-art and recent advances concerning the tunnelling FETs as energy efficient switches, capable of operating at sub-0.5V due to their low Ioff and steep subthermal subthreshold slope (better than 60mV/decade at room temperature). Overall, it appears that the engineering of heterojunction tunnelling FETs with the application of some technology boosters similar to advanced silicon CMOS can offer the appropriate path for a high performance complementary platform for this new family of devices. More aggressive scaling of their operation voltage, below 0.1V can be achieved with new concepts like the Electron-Hole Bilayer Tunnel FET exploiting the effect of low dimensionality on the Density of States (DOS).","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122551115","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998710
F. Fummi, M. Lora, D. Trachanis, J. Van Hese, S. Vinco
This work provides a taxonomy of abstraction levels and design domains of a smart system, for analyzing the support of simulation/co-simulation and the effect of homogeneity/heterogeneity on simulation. The paper presents also flows and tools that can be exploited to gain homogeneous simulation. The overall approach is applied to a complex industrial case study.
{"title":"Homogeneous simulation: The effective integration solution for smart systems","authors":"F. Fummi, M. Lora, D. Trachanis, J. Van Hese, S. Vinco","doi":"10.1109/ASDAM.2014.6998710","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998710","url":null,"abstract":"This work provides a taxonomy of abstraction levels and design domains of a smart system, for analyzing the support of simulation/co-simulation and the effect of homogeneity/heterogeneity on simulation. The paper presents also flows and tools that can be exploited to gain homogeneous simulation. The overall approach is applied to a complex industrial case study.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121450510","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998682
A. Bouřa, J. Kroutil
Presented work deals with crystal oscillators that can be used as a quartz crystal microbalance (QCM) gas sensor. There are presented two basic oscillators that are very common in literature. The oscillators were put into practice and tested in the gas chamber with different crystals of basic frequency 10 MHz. There were tested clean crystal resonators and resonators coated by a sensitive layer. Frequency response of the oscillators is usually very small and it is comparable with the effects such as temperature change or crosstalk in the evaluation circuit. The evaluation circuit thus must be designed carefully. Main goal of this paper is comparison of two basic designs of the oscillators and presentation of the precise evaluation circuit with minimal crosstalk and reverse transmission in signal ways.
{"title":"Precise beat frequency evaluation circuit for multi-oscillators QCM gas detectors","authors":"A. Bouřa, J. Kroutil","doi":"10.1109/ASDAM.2014.6998682","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998682","url":null,"abstract":"Presented work deals with crystal oscillators that can be used as a quartz crystal microbalance (QCM) gas sensor. There are presented two basic oscillators that are very common in literature. The oscillators were put into practice and tested in the gas chamber with different crystals of basic frequency 10 MHz. There were tested clean crystal resonators and resonators coated by a sensitive layer. Frequency response of the oscillators is usually very small and it is comparable with the effects such as temperature change or crosstalk in the evaluation circuit. The evaluation circuit thus must be designed carefully. Main goal of this paper is comparison of two basic designs of the oscillators and presentation of the precise evaluation circuit with minimal crosstalk and reverse transmission in signal ways.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121518280","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 : 2014-12-29DOI: 10.1109/ASDAM.2014.6998693
J. Zehetner, G. Vanko, P. Choleva, J. Dzuba, I. Ryger, T. Lalinsky
In order to improve the stability, sensitivity or efficiency of AlGaN/GaN based sensors employing high electron mobility transistors (HEMTs), Schottky diodes and/or resistors they should be integrated into micro-electro-mechanical-systems (MEMS). The creation of appropriate diaphragms and/or cantilevers is necessary for the verification of sensing properties of such MEMS sensors. In this paper, we present possible approaches to improve the fabrication of micromechanic structures in bulk SiC substrates with epitaxial AlGaN/GaN heterostructures using femtosecond laser ablation to fabricate SiC diaphragms. The objective of this work is also to point at the backside damaging effects and to find an optimal method for its elimination or suppression.
{"title":"Using of laser ablation technique in the processing technology of GaN/SiC based MEMS for extreme conditions","authors":"J. Zehetner, G. Vanko, P. Choleva, J. Dzuba, I. Ryger, T. Lalinsky","doi":"10.1109/ASDAM.2014.6998693","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998693","url":null,"abstract":"In order to improve the stability, sensitivity or efficiency of AlGaN/GaN based sensors employing high electron mobility transistors (HEMTs), Schottky diodes and/or resistors they should be integrated into micro-electro-mechanical-systems (MEMS). The creation of appropriate diaphragms and/or cantilevers is necessary for the verification of sensing properties of such MEMS sensors. In this paper, we present possible approaches to improve the fabrication of micromechanic structures in bulk SiC substrates with epitaxial AlGaN/GaN heterostructures using femtosecond laser ablation to fabricate SiC diaphragms. The objective of this work is also to point at the backside damaging effects and to find an optimal method for its elimination or suppression.","PeriodicalId":313866,"journal":{"name":"The Tenth International Conference on Advanced Semiconductor Devices and Microsystems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132464588","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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