Pub Date : 2014-12-29DOI: 10.1109/ASDAM.2014.6998650
T. Szymański, M. Wośko, B. Paszkiewicz, K. Indykiewicz, R. Paszkiewicz
In this paper the wide range of application of real time in situ reflectance signal observation based on four GaN on Si samples grown is shown. Mean reflectance value of oscillations for GaN growth and recovery times were extracted from reflectance traces acquired in situ. Moreover, RMS variation of grown samples were correlated with in situ monitoring that were in good agreement with presented model. We present what additional information can be extracted by in-situ interferometry.
{"title":"Application of real time in-situ interferometry for the observation of GaN/Si MOVPE growth process","authors":"T. Szymański, M. Wośko, B. Paszkiewicz, K. Indykiewicz, R. Paszkiewicz","doi":"10.1109/ASDAM.2014.6998650","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998650","url":null,"abstract":"In this paper the wide range of application of real time in situ reflectance signal observation based on four GaN on Si samples grown is shown. Mean reflectance value of oscillations for GaN growth and recovery times were extracted from reflectance traces acquired in situ. Moreover, RMS variation of grown samples were correlated with in situ monitoring that were in good agreement with presented model. We present what additional information can be extracted by in-situ interferometry.","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":"134336321","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.2014.6998692
E. Vavrinsky, D. Moskáľová, J. Mihálov, M. Donoval, M. Daricek, V. Stopjaková
The paper deals with simultaneous psychological application of two biosensor probes developed by two research groups. The first biosensor “Biosense” measures human surface biopotentials (namely cardiac activity (ECG)) and physical activity (acceleration). The second sensor “EDA-ring” measures resistance of human skin, so called electro-dermal activity (EDA).
{"title":"Complex measurement of human physiology using designed miniature wireless sensors","authors":"E. Vavrinsky, D. Moskáľová, J. Mihálov, M. Donoval, M. Daricek, V. Stopjaková","doi":"10.1109/ASDAM.2014.6998692","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998692","url":null,"abstract":"The paper deals with simultaneous psychological application of two biosensor probes developed by two research groups. The first biosensor “Biosense” measures human surface biopotentials (namely cardiac activity (ECG)) and physical activity (acceleration). The second sensor “EDA-ring” measures resistance of human skin, so called electro-dermal activity (EDA).","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":"133362304","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.2014.6998669
J. Marek, A. Šatka, D. Donoval, M. Molnar, J. Priesol, A. Chvála, P. Pribytny
Impact of structure geometry and bulk traps on the performance of the n++GaN/InAlN/AlN/GaN high electron mobility transistor (HEMT) using two-dimensional Sentaurus TCAD simulation tool were investigated. Simulations were performed by the electrophysical models calibrated on real devices. The results indicate a significant influence of both acceptor and donor traps on device switching characteristics.
{"title":"Influence of structure geometry and bulk traps on switching transients of InAlN/GaN HEMT","authors":"J. Marek, A. Šatka, D. Donoval, M. Molnar, J. Priesol, A. Chvála, P. Pribytny","doi":"10.1109/ASDAM.2014.6998669","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998669","url":null,"abstract":"Impact of structure geometry and bulk traps on the performance of the n++GaN/InAlN/AlN/GaN high electron mobility transistor (HEMT) using two-dimensional Sentaurus TCAD simulation tool were investigated. Simulations were performed by the electrophysical models calibrated on real devices. The results indicate a significant influence of both acceptor and donor traps on device switching characteristics.","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":"130133543","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.2014.6998659
C. Zervos, A. Bairamis, A. Adikimenakis, A. Kostopoulos, M. Kayambaki, K. Tsagaraki, G. Konstantinidis, A. Georgakilas
AlN/GaN/AlN double heterostructures grown by PAMBE on sapphire (0001) substrates with different AlN top barrier thicknesses, ranging between 1.5 and 4 nm, were investigated. The two-dimensional electron gas (2DEG) density increased with AlN barrier thickness in agreement with the theoretical values. The highest value of 2.2×1013 cm-2 for the HEMT structure with 4.5 nm AlN barrier thickness and the highest mobility of 900 cm2/Vs for the structure with 3 nm AlN barrier thickness were obtained. HEMT devices, processed with a gate length of 1μm, exhibited a maximum drain current of 1.1 A/mm for 3 and 3.7 nm AlN barrier thickness. The transistor threshold voltage scaled linearly from +0.2V to-2.7V by varying the AlN barrier thickness from 1.5 nm to 4.5 nm respectively showing a normally-off potential use.
{"title":"AlN/GaN/AlN double heterostructures with thin AlN top barriers","authors":"C. Zervos, A. Bairamis, A. Adikimenakis, A. Kostopoulos, M. Kayambaki, K. Tsagaraki, G. Konstantinidis, A. Georgakilas","doi":"10.1109/ASDAM.2014.6998659","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998659","url":null,"abstract":"AlN/GaN/AlN double heterostructures grown by PAMBE on sapphire (0001) substrates with different AlN top barrier thicknesses, ranging between 1.5 and 4 nm, were investigated. The two-dimensional electron gas (2DEG) density increased with AlN barrier thickness in agreement with the theoretical values. The highest value of 2.2×1013 cm-2 for the HEMT structure with 4.5 nm AlN barrier thickness and the highest mobility of 900 cm2/Vs for the structure with 3 nm AlN barrier thickness were obtained. HEMT devices, processed with a gate length of 1μm, exhibited a maximum drain current of 1.1 A/mm for 3 and 3.7 nm AlN barrier thickness. The transistor threshold voltage scaled linearly from +0.2V to-2.7V by varying the AlN barrier thickness from 1.5 nm to 4.5 nm respectively showing a normally-off potential use.","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":"114335948","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.2014.6998656
A. Vescan, H. Hahn, B. Reuters, H. Kalisch
For more than 20 years, the field of group III nitrides has been among the most exciting ones in solid-state device research. During this time, significant progress has been obtained not only from a technological point of view, but also and more importantly in terms of understanding these materials and their very specific properties.This paper gives a summary on our results on the growth of heterostructures based on quaternary barriers, the compositional control and the implications on crystal and electrical properties. The additional degree of freedom acquired by this capability is applied to a variety of device designs such as normally-off or high-ns structures with excellent transport properties. Finally, the formation of polarization-induced two-dimensional hole gases (2DHGs) in inverted heterostructures is demonstrated.
{"title":"Novel GaN-based transistors using polarization engineering","authors":"A. Vescan, H. Hahn, B. Reuters, H. Kalisch","doi":"10.1109/ASDAM.2014.6998656","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998656","url":null,"abstract":"For more than 20 years, the field of group III nitrides has been among the most exciting ones in solid-state device research. During this time, significant progress has been obtained not only from a technological point of view, but also and more importantly in terms of understanding these materials and their very specific properties.This paper gives a summary on our results on the growth of heterostructures based on quaternary barriers, the compositional control and the implications on crystal and electrical properties. The additional degree of freedom acquired by this capability is applied to a variety of device designs such as normally-off or high-ns structures with excellent transport properties. Finally, the formation of polarization-induced two-dimensional hole gases (2DHGs) in inverted heterostructures is demonstrated.","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":"128801979","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.2014.6998660
W. Jatal, K. Tonisch, U. Baumann, F. Schwierz, J. Pezoldt
We report on GaN HEMTs on Si substrates with high cutoff frequency and low contact resistance. HEMTs with two barriers designs and two source/drain metallization schemes have been fabricated and characterized. Our 100-nm gate transistors show a maximum drain current density of 1.4 A/mm and a peak transconductance of 427 mS/mm. The fastet transistors have a gate length of 80 nm and achieve a cutoff frequency fT of 180 GHz. This is the best fT performance reported for GaN HEMTs on Si reported so far and rivals the fastest GaN HEMTs on SiC with comparable gate length.
我们报道了在Si衬底上具有高截止频率和低接触电阻的GaN hemt。制备了具有两种阻挡层设计和两种源/漏金属化方案的hemt并对其进行了表征。我们的100纳米栅极晶体管的最大漏极电流密度为1.4 a /mm，峰值跨导为427 mS/mm。最快的晶体管栅极长度为80nm，截止频率为180ghz。这是迄今为止报道的硅基GaN hemt的最佳fT性能，与栅极长度相当的SiC上最快的GaN hemt相媲美。
{"title":"GaN HEMTs on Si substrate with high cutoff frequency","authors":"W. Jatal, K. Tonisch, U. Baumann, F. Schwierz, J. Pezoldt","doi":"10.1109/ASDAM.2014.6998660","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998660","url":null,"abstract":"We report on GaN HEMTs on Si substrates with high cutoff frequency and low contact resistance. HEMTs with two barriers designs and two source/drain metallization schemes have been fabricated and characterized. Our 100-nm gate transistors show a maximum drain current density of 1.4 A/mm and a peak transconductance of 427 mS/mm. The fastet transistors have a gate length of 80 nm and achieve a cutoff frequency fT of 180 GHz. This is the best fT performance reported for GaN HEMTs on Si reported so far and rivals the fastest GaN HEMTs on SiC with comparable gate length.","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":"121593718","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.2014.6998708
K. Cavanagh, C. Liu, T. Martin, M. Hopkins, S. Sivaraya, D. Allsopp
Green - orange light emitting diodes of were fabricated from InGaN/GaN wafers grown by MOVPE. Detailed measurements of the current and spectral dependence of their electroluminescence were made under low noise DC and pulsed conditions. The results revealed that low electrical to optical power conversion efficiency correlates with degrade current-voltage characteristics.
{"title":"Detailed optical and electrical characterisation of green — Orange InGaN/GaN LEDs grown by MOVPE","authors":"K. Cavanagh, C. Liu, T. Martin, M. Hopkins, S. Sivaraya, D. Allsopp","doi":"10.1109/ASDAM.2014.6998708","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998708","url":null,"abstract":"Green - orange light emitting diodes of were fabricated from InGaN/GaN wafers grown by MOVPE. Detailed measurements of the current and spectral dependence of their electroluminescence were made under low noise DC and pulsed conditions. The results revealed that low electrical to optical power conversion efficiency correlates with degrade current-voltage characteristics.","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":"117043891","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.2014.6998686
C. Burtscher, D. Seyringer, F. Uherek, J. Chovan, A. Kuzma
We present the design and simulation of low loss 1 × 64 Y-branch optical splitter having the symmetric splitting ratio and small footprint. This was reached by optimizing the used waveguide structure that eliminates the presence of the first mode, causing the asymmetric splitting ratio of the split power over all the output waveguides. This way we were able to reduce the length of the splitter to nearly one third of its original designed value.
{"title":"Design of low loss 1×64 y-branch splitter having symmetric splitting ratio and small footprint","authors":"C. Burtscher, D. Seyringer, F. Uherek, J. Chovan, A. Kuzma","doi":"10.1109/ASDAM.2014.6998686","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998686","url":null,"abstract":"We present the design and simulation of low loss 1 × 64 Y-branch optical splitter having the symmetric splitting ratio and small footprint. This was reached by optimizing the used waveguide structure that eliminates the presence of the first mode, causing the asymmetric splitting ratio of the split power over all the output waveguides. This way we were able to reduce the length of the splitter to nearly one third of its original designed value.","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":"133326272","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.2014.6998643
F. Dubecký, B. Zat’ko, G. Vanko, P. Hubík, J. Oswald, D. Kindl, E. Gombia, J. Kováč, A. Šagátová, V. Nečas
M/Semi-insulating (SI) GaAs/M diodes with novel Mg-based metallization are investigated using current-voltage measurement, α-particle and photon detection. An anomalous decrease of the reverse current and peculiar photon spectra has been observed with such contact explainable by a strong electron accumulation due to the creation of a quasi-degenerate region at the Mg/SI-GaAs interface.
{"title":"M/Si-GaAs/M diode: Role of the metal contact in electrical transport, a-particle and photon detection","authors":"F. Dubecký, B. Zat’ko, G. Vanko, P. Hubík, J. Oswald, D. Kindl, E. Gombia, J. Kováč, A. Šagátová, V. Nečas","doi":"10.1109/ASDAM.2014.6998643","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998643","url":null,"abstract":"M/Semi-insulating (SI) GaAs/M diodes with novel Mg-based metallization are investigated using current-voltage measurement, α-particle and photon detection. An anomalous decrease of the reverse current and peculiar photon spectra has been observed with such contact explainable by a strong electron accumulation due to the creation of a quasi-degenerate region at the Mg/SI-GaAs interface.","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":"125719481","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.2014.6998665
M. Uren, Martin Kuball
GaN based transistors are vulnerable to long time period instabilities as a result of the wide bandgap. In this paper we review the effect of the bulk GaN dopants, which are added to ensure a highly resistive buffer, on the current-collapse which occurs on switching from the off-state to the on-state. The iron doping frequently used in RF devices leads to a trap level in the upper half of the gap which generates a small, reproducible, and straightforwardly modelled current-collapse. On the other hand the carbon doping used in many power devices results in current-collapse which can be large but is strongly impacted by the presence of leaky threading dislocations. A powerful technique to characterise the buffer and extract the vertical leakage in the different layers within a GaN-n-Si power HEMT based on ramping the substrate bias is introduced.
{"title":"GaN transistor reliability and instabilities","authors":"M. Uren, Martin Kuball","doi":"10.1109/ASDAM.2014.6998665","DOIUrl":"https://doi.org/10.1109/ASDAM.2014.6998665","url":null,"abstract":"GaN based transistors are vulnerable to long time period instabilities as a result of the wide bandgap. In this paper we review the effect of the bulk GaN dopants, which are added to ensure a highly resistive buffer, on the current-collapse which occurs on switching from the off-state to the on-state. The iron doping frequently used in RF devices leads to a trap level in the upper half of the gap which generates a small, reproducible, and straightforwardly modelled current-collapse. On the other hand the carbon doping used in many power devices results in current-collapse which can be large but is strongly impacted by the presence of leaky threading dislocations. A powerful technique to characterise the buffer and extract the vertical leakage in the different layers within a GaN-n-Si power HEMT based on ramping the substrate bias is introduced.","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":"132775101","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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