Ing. Roman STOKLAS, PhD.

  • 2019

Gregušová, D., Tóth, L., Pohorelec, O., Hasenöhrl, S., Haščík, Š., Cora, I., Fogarassy, Z., Stoklas, R., Seifertová, A., Blaho, M., Laurenčíková, A., Oyobiki, T., Pécz, B., Hashizume, T., and Kuzmík, J.: InGaN/(GaN)/AlGaN/GaN normally-off metal-oxide-semiconductor high-electron mobility transistors with etched access region, Japan. J. Applied Phys. 58 (2019) SCCCD21.

Chauhan, P., Hasenöhrl, S., Dobročka, E., Vančo Ľ., Stoklas, R., Kováč, J., Šiffalovič, P., and Kuzmík, J.: Effect of temperature and carrier gas on the properties of thick InxAl1-xN layer, Applied Surface Sci 470 (2019) 1-7.

Hasenöhrl, S., Chauhan, P., Dobročka, E., Stoklas, R., Vančo, Ľ., Veselý, M., Bouazzaoui, F., Chauvat, M.-P., Reterana, P., and Kuzmík, J.: Generation of hole gas in non-inverted InAl(Ga)N/GaN heterostructures, Applied Phys. Express 12 (2019) 014001.

  • 2018

Stoklas, R., Gregušová, D., Hasenöhrl, S., Brytavskyi, I.V., Ťapajna, M., Fröhlich, , Haščík, Š., Gregor, M., and Kuzmík, J.: Characterization of interface states in AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with HfO2 gate dielectric grown by atomic layer deposition, Applied Surface Sci 461 (2018) 255-259.

Kúdela, R., Šoltýs, J., Kučera, M., Stoklas, R., Gucmann, F., Blaho, J., Mičušík, M., Pohorelec, O., Gregor, M., Brytavskyi, I.V., Dobročka, E., and Gregušová, D.: Technology and application of in-situ AlOx layers on III-V semiconductors, Applied Surface Sci 461 (2018) 33-38.

  • 2017
Brytavskyi, I., Gregušová, D., Ťapajna, M., Stoklas, R., Blaho, M., Seifertová, A., Hasenöhrl, S., Dobročka, E., Kuzmík, J., : Hafnium oxide as a promising material for gate isolation in GaN-based MOS HFETs In: Proc. ADEPT. 5st Inter. Conf. on Advan. in Electronic and Photonic Technol. Eds. I. Lettrichová et al. Žilina: Univ. Žilina 2017. ISBN 978-80-554-1342-6. P. 207-210..

 

Stoklas, R., Gregušová, D., Blaho, M., Fröhlich, K., Novák, J., Matys, M., Yatabe, Z., Kordoš, P., Hashizume, T., : Influence of oxygen-plasma treatment on AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with HfO2 by atomic layer deposition: leakage current and density of states reduction,. Semicond. Sci Technol. 32 (2017) 045018.

 

Ťapajna, M., Stoklas, R., Gregušová, D., Gucmann, F., Hušeková, K., Haščík, Š., Fröhlich, K., Tóth, L., Pecz, B., Brunner, F., Kuzmík, J., : Investigation of ‘surface donors’ in Al2O3/AlGaN/GaN metal-oxide-semiconductor heterostructures: Correlation of electrical, structural, and chemical properties. Applied Surface Sci 426 (2017) 656-661.

 

Matys, M., Stoklas, R., Blaho, M., Adamowicz, J., : Origin of positive fixed charge at insulator/AlGaN interfaces and its control by AlGaN composition. Applied Phys. Lett. 110 (2017) 243505.

 

Gregušová, D., Gucmann, F., Kúdela, R., Mičušík, M., Stoklas, R., Válik, L., Greguš, J., Blaho, M., Kordoš, P., : Properties of InGaAs/GaAs metal-oxide-semiconductor heterostructure field-effect transistors modified by surface treatment,. Applied Surface Sci 395 (2017) 140-144.

 

Florovič, M., Stoklas, R., Kováč, J., Kordoš, P., : Temperature-induced instability of the threshold voltage in GaN-based heterostructure field-effect transistors,. Semicond. Sci Technol. 32 (2017) 025017.

 

  • 2016
Matys, M., Stoklas, R., Kuzmík, J., Adamowicz, J., Yatabe, Z., Hashizume, T., : Characterization of capture cross sections of interface states in dielectric/III-nitride heterojunction structures. J. Applied Phys. 119 (2016) 205304.

 

Matys, M., Adamowicz, J., Domanowska, A., Michalewicz, A., Stoklas, R., Akazawa, M., Yatabe, Z., Hashizume, T., : On the origin of interface states at oxide/III-nitride heterojunction interfaces. J. Applied Phys. 119 (2016) 225305.

 

Stoklas, R., Gregušová, D., Fröhlich, K., Kuzmík, J., : Temperature-dependent of sub-threshold slope of AlGaN/GaN MOSHFETs with HfO2 gate oxide prepared by ALD In: ASDAM 2016. Eds. Š. Haščík et al. IEEE 2016. ISBN 978-1-5090-3081-1. P. 189-192.

 

  • 2015
Osvald, J., Stoklas, R., Kordoš, P., : Extraction of interface trap density of Al2O3/AlGaN/GaN MIS heterostructure capacitance. Phys. Status Solidi B 252 (2015) 996-1000.

 

Osvald, J., Stoklas, R., Kordoš, P., : Low- and high-frequency capacitance of aluminum gallium nitride/gallium nitride heterostructures with interface traps. Mater. Sci in Semicond. Process. 31 (2015) 525-529.

 

Gregušová, D., Kúdela, R., Gucmann, F., Stoklas, R., Blaho, M., Ťapajna, M., Kordoš, P., Fröhlich, K., : Technology and application of in-situ alox layers on III-V semiconductors. In: Progress in Applied Surface, Interface and Thin Film Sci. 2015 – SURFINT-SREN IV. Extend. Abstract Book. Ed. R. Brunner. Bratislava: CU 2015. ISBN: 978-80-223-3975-9. P. 58.

 

  • 2014
Stoklas, R., Gregušová, D., Blaho, M., Čičo, K., Fröhlich, K., Novák, J., Kordoš, P., : Gate leakage reduction of AlGaN/GaN MOS-HFETs with HfO2 prepared by ALD In: ASDAM 2014. Eds. J. Breza et al. IEEE 2014. ISBN 978-1-4799-5474-2. P. 133-136.

 

Gucmann, F., Kúdela, R., Fröhlich, K., Liday, J., Vogrinčič, P., Gaži, Š., Stoklas, R., Kordoš, P., Novák, J., Gregušová, D., : III-As high electron mobility transistors with recessed ex-situ gate oxide In: Proc. ADEPT. 2st Inter. Conf. on Advan. in Electronic and Photonic Technol. Eds. D. Pudis et al. Žilina: Univ. Žilina 2014. ISBN 978-80-554-0881-1. P. 5-8.

 

Gucmann, F., Gregušová, D., Stoklas, R., Dérer, J., Kúdela, R., Fröhlich, K., Kordoš, P., : InGaAs/GaAs metal-oxide-semiconductor heterostructure field-effect transistors with oxygen-plasma oxide and Al2O3 double-layer insulator. Applied Phys. Lett. 105 (2014) 183504.

 

Stoklas, R., Gregušová, D., Hušeková, K., Marek, J., Kordoš, P., : Trapped charge effects in AlGaN/GaN metal-oxide-semiconductor structures with Al2O3 and ZrO2 gate insulator. Semicond. Sci Technol. 29 (2014) 045003.

 

  • 2013
Kordoš, P., Stoklas, R., Gregušová, D., Hušeková, K., Carlin, J., Grandjean, N., : Defect states characterization of non-annealed and annealed Zr2/InAlN/GaN structures by capacitance measurements,. Applied Phys. Lett. 102 (2013) 063502.

 

Kordoš, P., Stoklas, R., Hušeková, K., Gregušová, D., : Characterization of GaN-based MOS structures by capacitance measurements. In: Proc. ADEPT. 1st Inter. Conf. on Advan. in Electronic and Photonic Technol. Eds. D. Pudis et al. Žilina: Univ. Žilina 2013. ISBN 978-80-554-0689-3. P. 28-31.

 

Laurenčíková, A., Hasenöhrl, S., Eliáš, P., Stoklas, R., Blaho, M., Novotný, I., Križanová, Z., Novák, J., :Ohmic contacts to p-GaP/n-ZnO core/shell nanowires based on Au metallization. Applied Surface Sci 267 (2013) 60-64.

 

Hasenöhrl, S., Eliáš, P., Šoltýs, J., Stoklas, R., Laurenčíková, A., Novák, J., : Zinc-doped gallium phosphide nanowires for photovoltaic structures,. Applied Surface Sci 269 (2013) 72-76.

 

Gregušová, D., Hušeková, K., Stoklas, R., Blaho, M., Jurkovič, M., Carlin, J., Grandjean, N., and Kordoš, P.: Zr2/InAlN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with InAlN barrier of different compositions, Japan. J. Applied Phys. 52 (2013) 08JN07.

 

  • 2012
Kordoš, P., Kúdela, R., Stoklas, R., Čičo, K., Mikulics, M., Gregušová, D., Novák, J., : Aluminum oxide as passivation and gate insulator in GaAs-based field-effect transistors prepared in situ by metal-organic vapor deposition. Applied Phys. Lett. 100 (2012) 142113.

 

Stoklas, R., Gregušová, D., Novák, J., Kordoš, P., Tajima, M., Hashizume, T., : Current instabilities and other reliability aspects in AlGaN/GaN MOS-HFETs with atomic layer deposited Al2O3 as gate oxide. In: ASDAM 2012. Eds. Š. Haščík, J. Osvald. Piscataway: IEEE 2012. ISBN 978-1-4673-1195-3. P. 36-40.

 

Kúdela, R., Gregušová, D., Stoklas, R., : Devices with Te-doped InGaP layers. In: ASDAM 2012. Eds. Š. Haščík, J. Osvald. Piscataway: IEEE 2012. ISBN 978-1-4673-1195-3. P. 111-114.

 

Novák, J., Šoltýs, J., Eliáš, P., Hasenöhrl, S., Stoklas, R., Laurenčíková, A., Mikulics, M., : Electrical and photoluminescence properties of individual GaP nanowires doped by zinc Phys. Status Solidi a 209 (2012) 2505-2509.

 

Kordoš, P., Fox, A., Kúdela, R., Mikulics, M., Stoklas, R., Gregušová, D., : GaAs-based metal-oxide-semiconductor field-effect transistor with aluminum oxide gate insulator prepared in situ by MOCVD. Semicond. Sci Technol. 27 (2012) 115002.

 

Novák, J., Novotný, I., Kováč, J., Eliáš, P., Hasenöhrl, S., Križanová, Z., Vávra, I., Stoklas, R., : Preparation of thin Ga-doped ZnO layers for core–shell GaP/ZnO nanowires. Applied Surface Sci 258 (2012) 7607-7611.

 

Gregušová, D., Kúdela, R., Stoklas, R., Blaho, M., Gucmann, F., Fedor, J., Kordoš, P., : The influence of an AlOx film in-situ deposited on the GaAs-based HFETs properties. In: ASDAM 2012. Eds. Š. Haščík, J. Osvald. Piscataway: IEEE 2012. ISBN 978-1-4673-1195-3. P. 107-110.

 

Kordoš, P., Mikulics, M., Stoklas, R., Čičo, K., Dadgar, A., Grützmacher, D., Krost, A., : Thermally oxidized InAlN of different compositions for InAlN/GaN heterostructure field-effect transistors. J. Electronic Mater. 41 (2012) 3013-3016.

 

  • 2011
Čičo, K., Hušeková, K., Ťapajna, M., Gregušová, D., Stoklas, R., Kuzmík, J., Carlin, J., Grandjean, N., Pogany, D., Fröhlich, K., : Electrical properties of InAlN/GaN high electron mobility transistor with Al2O3, ZrO2, and GdScO3 gate dielectrics. J. Vacuum Sci Technol. B 29 (2011) 01A808.

 

Stoklas, R., Gregušová, D., Gaži, Š., Novák, J., Kordoš, P., : Performance of AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistors with AlN gate insulator prepared by reactive magnetron sputtering. J. Vacuum Sci Technol. B 29 (2011) 01A809.

 

  • 2010
Gregušová, D., Hori, Y., Mizue, C., Stoklas, R., Sugawara, K., Hashizume, T., Kordoš, P., : Density of trap states in Al2O3/AlGaN/GaN MOS structures with gate oxide prepared by atomic layer deposition. In: Inter. RCIQE/CREST Joint Workshop 2010. Hokkaido Univ. 2010. P. 34-35.

 

Mikulics, M., Stoklas, R., Dadgar, A., Gregušová, D., Novák, J., Grützmacher, D., Krost, A., Kordoš, P., :InAlN/GaN/Si heterostructures and field-effect transistors with lattice matched and tensely or compressively strained InAlN. Applied Phys. Lett. 97 (2010) 173505.

 

Gregušová, D., Gaži, Š., Sofer, Z., Stoklas, R., Dobročka, E., Mikulics, M., Greguš, J., Novák, J., Kordoš, P., : Oxidized Al film as an insulation layer in AlGaN/GaN Metal–Oxide–Semiconductor heterostructure field effect transistors Japan. J. Applied Phys. 49 (2010) art. no. 046504.

 

Stoklas, R., Gregušová, D., Blaho, M., Kordoš, P., Tajima, M., Hashizume, T., : Preparation and properties of AlGaN/GaN MOS-HFETs with atomic layer deposited Al2O3 as gate oxide. In: ASDAM ’10. Ed. J. Breza et al. Piscataway: IEEE 2010. ISBN: 978-1-4244-8572-7. P. 155-158.

 

Gregušová, D., Stoklas, R., Mizue, C., Hori, Y., Novák, J., Hashizume, T., Kordoš, P., : Trap states in AlGaN/GaN metal-oxide-semiconductor structures with Al2O3 prepared by atomic layer deposition. J. Applied Phys. 107 (2010) 106104.

 

Kordoš, P., Stoklas, R., Gregušová, D., Gaži, Š., Novák, J., : Trapping effects in Al2O3/AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistor investigated by temperature dependent conductance measurement. Applied Phys. Lett. 96 (2010) 013505.

 

Gregušová, D., Mizue, C., Hori, Y., Stoklas, R., Novák, J., Hashizume, T., Kordoš, P., : Trapping effects in Al2O3/AlGaN/GaN MOS structures with gate oxide prepared by different deposition techniques. . In: 10th Expert Evaluation & Control Compound Semicond Mater. & Technol. – EXMATEC 2010. Eds. D. Pavlidis et al. Darmstadt/Seeheim: TU Darmstadt 2010. ISBN: 978-3-00-030837-6. P. 139-140.

 

  • 2009
Kúdela, R., Gregušová, D., Stoklas, R., Šoltýs, J., Kučera, M., Dobročka, E., Kordoš, P., : HEMT transistors with aluminum oxide and InGaP layers. In: EW-MOVPE XIII. Ulm Univ. 2009. P. 225-228.

 

Kordoš, P., Stoklas, R., Gregušová, D., Novák, J., : Characterization of AlGaN/GaN metal-oxide-semiconductor field-effect transistors by frequency dependent conductance analysis. Applied Phys. Lett. 94 (2009) 223512.

 

Gregušová, D., Stoklas, R., Eickelkamp, M., Fox, A., Novák, J., Vescan, A., Grützmacher, D., Kordoš, P., :Characterization of AlGaN/GaN MISHFETs on a Si substrate by static and high-frequency measurements. Semicond. Sci Technol. 24 (2009) 075014.

 

Kordoš, P., Fox, A., Stoklas, R., Eickelkamp, M., Gregušová, D., Grützmacher, D., Vescan, A., : Improved high-frequency performance of Al2O3/AlGaN/GaN MISHFETs compared to AlGaN/GaN HFETs. In: APCOM 2009. Eds. D. Pudiš et al. Žilina: Univ. Žilina 2009. ISBN: 978-80-554-0057-0. P. 25-28.

 

  • 2008
Stoklas, R., Gaži, Š., Gregušová, D., Novák, J., Kordoš, P., : Enhancement of effective carrier velocity in AlGaN/GaN MOSHFETs with Al2O3 gate oxide. Physica Status Solidi c 5 (2008) 1935-1937.

 

Kordoš, P., Florovič, M., Stoklas, R., Gregušová, D., Donoval, D., : Characterization of Al2O3/AlGaN/GaN MOSHFETs AND AlGaN/GaN HFET by measurements at elevated temperatures. In: APCOM 2008. Eds. J. Vajda et al. Bratislava: FEI STU, 2008. P. 109-112.

 

Stoklas, R., Gregušová, D., Novák, J., Kordoš, P., : Influence of annealing on electrical properties of AlGaN/GaN HFETs and MOSHFETs using Al2O3. In: ASDAM 2008. Eds. Š. Haščík and J.Osvald. Piscataway: IEEE 2008. ISBN: 978-1-4244-2325-5. P. 263-266.

 

Stoklas, R., Gregušová, D., Novák, J., Vescan, A., Kordoš, P., : Investigation of trapping effects in AlGaN/GaN/Si field-effect transistors by frequency dependent capacitance and conductance analysis. Applied Phys. Lett. 93 (2008) 124103.

 

Kordoš, P., Gregušová, D., Stoklas, R., Gaži, Š., Novák, J., : Transport properties of AlGaN/GaN metal–oxide–semiconductor heterostructure field-effect transistors with Al2O3 of different thickness,. Solid-State Electr. 52 (2008) 973-979.

 

  • 2007
Gregušová, D., Stoklas, R., Čičo, K., Lalinský, T., Kordoš, P., : AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with 4nm thick Al2O3 gate oxide. Semicond. Sci Technol. 22 (2007) 947-951.

 

Gregušová, D., Stoklas, R., Čičo, K., Heidelberg, G., Marso, M., Novák, J., Kordoš, P., : Characterization of AlGaN/GaN MOSHFETs with Al2O3 as gate oxide, Physica Status Solidi c 4 (2007) 2720-2723.

 

Kordoš, P., Gregušová, D., Stoklas, R., Čičo, K., Novák, J., : Improved transport properties of Al2O3/AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect tranzistor. Applied Phys. Lett. 90 (2007) 123513.

 

Čičo, K., Kuzmík, J., Gregušová, D., Stoklas, R., Lalinský, T., Georgakilas, A., Pogany, D., Fröhlich, K., :Optimization and performance of Al2O3/GaN metal-oxide-semiconductor structures. Microelectr. Reliability 47 (2007) 790-793.

 

Gregušová, D., Stoklas, R., Čičo, K., Lalinský, T., Fröhlich, K., Novák, J., Kordoš, P., : Preparation and properties of MOSHFETs based on MOVPE grown AlGaN/GaN heterostructure and MOCVD deposited Al2O3 gate oxide. In: EW-MOVPE XII: extended abstracts. Bratislava: IEE SAS, 2007. P. 85-88.

 

Kordoš, P., Gregušová, D., Stoklas, R., Lalinský, T., Novák, J., : Transconductance enhancement in AlGaN/GaN MOSHEFTs with Al2O3 gate oxide. In: Proc. 31st Workshop on Compound Semiconductor Devices and Integrated Circuits. Ed. G. Meneghesso. Venice: 2007. P. 381-384.

 

  • 2006
Stoklas, R., Čičo, K., Gregušová, D., Novák, J., Kordoš, P., : Preparation and properties of AlGaN/GaN MOSHFETs with MOCVD Al2O3 as gate oxide. In: ASDAM 2006. Piscataway: IEEE 2006. ISBN: 1-4244-0396-0. P. 249-252.