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Usman, Muhammad
Publications (2 of 2) Show all publications
Usman, M., Arshad, M., Suvanam, S. S. & Hallen, A. (2018). Influence of annealing environment on the ALD-Al2O3/4H-SiC interface studied through XPS. Journal of Physics D: Applied Physics, 51(10), Article ID 105111.
Open this publication in new window or tab >>Influence of annealing environment on the ALD-Al2O3/4H-SiC interface studied through XPS
2018 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, no 10, article id 105111Article in journal (Refereed) Published
Abstract [en]

The instability of Al2O3/4H-SiC interface at various process temperatures and ambient is investigated by the annealing of Al2O3/4H-SiC in low vacuum conditions as well as in N-2 environments. Atomic layer deposited Al2O3 on a 4H-SiC substrate with 3, 6 and 10 nm of thicknesses is treated at 300, 500, 700 and 900 degrees C under the vacuum level of 10(-1) torr. The as-deposited and annealed structures are analyzed using x-ray photoelectron spectroscopy. It is hypothesized that the minute quantity of oxygen present in low vacuum conditions diffuses through thin layers of Al2O3 and helps in forming SiO2 at the interface even at low temperatures (i.e. 300 degrees C), which plays a pivotal role in determining the electrical properties of the interface. It is also proved that the absence of oxygen in the ambient prevents the formation of SiO2 at low temperatures. Additionally, it is observed that Al-OH is present in as-deposited layers, which gradually reduces after annealing. However, at around 700 degrees C, the concentration of oxygen in the whole structure increases to maximum and reduces at 900 degrees C.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2018
Keywords
Al2O3/4H-SiC interface, oxygen diffusion, annealing, XPS
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-224005 (URN)10.1088/1361-6463/aaa9a1 (DOI)000425627200003 ()2-s2.0-85042358184 (Scopus ID)
Note

QC 20180319

Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-03-19Bibliographically approved
Linnarsson, M. K., Hallén, A., Khartsev, S., Suvanam, S. S. & Usman, M. (2017). Interface between Al2O3 and 4H-SiC investigated by time-of-flight medium energy ion scattering. Journal of Physics D: Applied Physics, 50(49), Article ID 495111.
Open this publication in new window or tab >>Interface between Al2O3 and 4H-SiC investigated by time-of-flight medium energy ion scattering
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2017 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, no 49, article id 495111Article in journal (Refereed) Published
Abstract [en]

The formation of interfacial oxides during heat treatment of dielectric films on 4H-SiC has been studied. The 4H-SiC surface has been carefully prepared to create a clean and abrupt interface to Al2O3. An amorphous, 3 nm thick, Al2O3 film has been prepared on 4H-SiC by atomic layer deposition and rapid thermal annealing was then performed in N2O ambient at 700 degrees C and 1100 degrees C during 1 min. The samples were studied by time-of-flight medium energy ion scattering (ToF-MEIS), with sub-nanometer depth resolution and it is seen that, at both annealing temperatures, a thin SiOx (1 <= x <= 2) is formed at the interface. Our results further indicate that carbon remains in the silicon oxide in samples annealed at 700 degrees C. Additional electrical capacitance voltage measurements indicate that a large concentration of interface traps is formed at this temperature. After 1100 degrees C annealing, both MEIS and XRD measurements show that these features disappear, in accordance with electrical data.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2017
Keywords
ALD, ToF-MEIS, 4H-SiC, Al2O3, interface
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-219324 (URN)10.1088/1361-6463/aa9431 (DOI)000415834100006 ()2-s2.0-85039788159 (Scopus ID)
Funder
Swedish Research Council, E0510501; D0674701
Note

QC 20171205

Available from: 2017-12-05 Created: 2017-12-05 Last updated: 2019-05-13Bibliographically approved
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