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Gallium nitride templates and its related materials for electronic and photonic devices
KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

 

Place, publisher, year, edition, pages
Stockholm: KTH , 2008. , xiv, 89 p.
Series
Trita-ICT/MAP AVH, ISSN 1653-7610 ; 2008:8
Keyword [en]
GaN, heteroepitaxy of GaN, BGaAlN, Fe doped GaN, HEMT, carrier capture cross section, intersubband transition modulator
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-4759ISBN: 978-91-7178-981-5 (print)OAI: oai:DiVA.org:kth-4759DiVA: diva2:13802
Public defence
2008-06-05, N2, Electrum 3, Isafjordsgatan 28 A/D, Kista, 10:15
Opponent
Supervisors
Note
QC 20100623Available from: 2008-05-16 Created: 2008-05-16 Last updated: 2010-09-20Bibliographically approved
List of papers
1. Investigation of the interface properties of MOVPE grown AlGaN/GaN high electron mobility transistor (HEMT) structures on sapphire
Open this publication in new window or tab >>Investigation of the interface properties of MOVPE grown AlGaN/GaN high electron mobility transistor (HEMT) structures on sapphire
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2006 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, 705-707 p.Article in journal (Refereed) Published
Abstract [en]

We have developed a virtual GaN substrate on sapphire based on a two-step growth method. By optimizing the growth scheme for the virtual substrate we have improved crystal quality and reduced interface roughness. Our Al0.22Ga0.78N/GaN HEMT structure grown on the optimized semi-insulating GaN virtual substrate, exhibits Hall mobilities as high as 1720 and 7350 cm(2)/Vs and sheet carrier concentrations of 8.4 x 1012 and 10.0 x 1012 cm(-2) at 300 K and 20 K, respectively The presence of good AlGaN/GaN interface quality and surface morphology is also substantiated by X-Ray reflectivity and Atomic Force Microscopy measurements. A simplified transport model is used to fit the experimental Hall mobility.

Keyword
MOVPE, HEMT, scattering, interface roughness, X-ray reflectivity, dislocations, CHEMICAL-VAPOR-DEPOSITION, GAN, HETEROSTRUCTURES
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-13646 (URN)10.1016/j.tsf.2006.04.052 (DOI)000241220600078 ()2-s2.0-33748909151 (Scopus ID)
Note
QC 20100622Available from: 2010-06-22 Created: 2010-06-22 Last updated: 2017-12-12Bibliographically approved
2. AlGaN/GaN high-electron-mobility transistors on sapphire with Fe-doped GaN buffer layer by MOVPE
Open this publication in new window or tab >>AlGaN/GaN high-electron-mobility transistors on sapphire with Fe-doped GaN buffer layer by MOVPE
2006 (English)In: Physica Status Solidi C - Current Topics in Solid State Physics: Vol 3, No 6 / [ed] Hildebrandt S; Stutzmann M, 2006, Vol. 3, 2373-2376 p.Conference paper, Published paper (Refereed)
Abstract [en]

A simple AlGaN/GaN HEMT structure without any interlayer on Fe-doped GaN (GaN:Fe) grown by LP-MOVPE in one single run on sapphire is demonstrated. The surface segregation of Fe in GaN occurring during growth is identified. Hall measurements yield 2DEG (two dimensional electron gas) mobilities of 1700 and 10700 cm2/Vs and sheet carrier concentrations of 5.1×10 12 and 5.7×1012 cm-2 at 300 K and 20 K, respectively. Good pinch-off current-voltage (ID-VD) characteristics is observed from AlGaN/GaN HEMTs. A maximum drain current density of 0.6 A/mm and a peak extrinsic transconductance of 200 mS/mm have been observed. The HEMT structure yields very good device isolation as indicated by an isolation current of ≀1 nA at 20 V.

Series
PHYSICA STATUS SOLIDI C-CURRENT TOPICS IN SOLID STATE PHYSICS, ISSN 1610-1634 ; Volume: 3, Issue: 6
Keyword
AlGaN/GaN high-electron-mobility transistors; Device isolation; Drain current density; GaN buffer, Current density; Doping (additives); Electron gas; Gallium nitride; Iron; Semiconducting aluminum compounds; Silicon on sapphire technology, High electron mobility transistors
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-13656 (URN)10.1002/pssc.200565152 (DOI)000239543600233 ()2-s2.0-33746371379 (Scopus ID)
Conference
6th International Conference on Nitride Semiconductors (ICNS-6), Bremen, GERMANY, AUG 28-SEP 02, 2005
Note
QC 20100623Available from: 2010-06-23 Created: 2010-06-22 Last updated: 2010-06-23Bibliographically approved
3. Electron and hole capture cross-sections of Fe acceptors in GaN:Fe epitaxially grown on sapphire
Open this publication in new window or tab >>Electron and hole capture cross-sections of Fe acceptors in GaN:Fe epitaxially grown on sapphire
Show others...
2007 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 36, no 12, 1621-1624 p.Article in journal (Refereed) Published
Abstract [en]

Carrier trapping of Fe (3+)/Fe2+ deep acceptors in epitaxially grown GaN:Fe on sapphire was studied by time-resolved photoluminescence. For the investigated Fe doping levels on the order of 10(18) cm(-3), the luminescence decay times are strongly dependent on the Fe concentration, indicating that Fe centers act as predominant nonradiative recombination channels. Linear dependence of the decay time on the iron concentration allows estimation of the electron capture cross-section for the Fe3+ ions, which is equal to 1.9 x 10(-15) cm(2). The upper bound for the cross-section of the hole capture of Fe2+ was evaluated as 10 x 10(-15) cm

Keyword
GaN, Fe, semi-insulating, high electron mobility transistor (HEMT), deep acceptor, electron capture cross section, metal-organic vapor phase epitaxy (MOVPE), OPTICAL-PROPERTIES, LAYERS, LEVEL, IRON, INP
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-13653 (URN)10.1007/s11664-007-0202-9 (DOI)000250884200014 ()2-s2.0-36148953872 (Scopus ID)
Note
QC 20100623Available from: 2010-06-22 Created: 2010-06-22 Last updated: 2017-12-12Bibliographically approved
4. Growth of GaN by metal organic vapor phase epitaxy on ZnO-buffered c-sapphire substrates
Open this publication in new window or tab >>Growth of GaN by metal organic vapor phase epitaxy on ZnO-buffered c-sapphire substrates
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2008 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 310, no 5, 944-947 p.Article in journal (Refereed) Published
Abstract [en]

The materials quality and availability of large-area bulk GaN substrates is currently considered a key problem for the continuing development of improved GaN-based devices. Since industrial fabrication of bulk GaN substrates with suitable materials quality has proven very difficult, the opto-GaN industry is currently based on heteroepitaxy using either c-sapphire or 6H SiC substrates. ZnO is promising as a substrate material for GaN because it has the same wurtzite structure and a relatively small lattice mismatch (similar to 1.8%). In this study, we have successfully grown GaN by MOVPE on ZnO-buffered c-sapphire. The growth conditions required to both prevent ZnO degradation and grow monocrystal thin film of GaN have been obtained. SEM, HRXRD and micro-Raman characterizations underlined the presence of the two layers GaN and ZnO with high structural quality.

Keyword
MOVPE, GaN, ZnO, LAYERS
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-13694 (URN)10.1016/j.jcrysgro.2007.11.137 (DOI)000254428100016 ()2-s2.0-39549115245 (Scopus ID)
Note
QC 20100623Available from: 2010-06-23 Created: 2010-06-23 Last updated: 2017-12-12Bibliographically approved
5. GaN thin films on z- and x-cut LiNbO3 substrates by MOVPE
Open this publication in new window or tab >>GaN thin films on z- and x-cut LiNbO3 substrates by MOVPE
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2008 (English)In: PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS: VOL 5, NO 6 / [ed] Palacios T.; Jena D., 2008, Vol. 5, 1565-1567 p.Conference paper, Published paper (Refereed)
Abstract [en]

We report epitaxial growth of GaN layers on z- and x-cut LiNbO3 substrates using MOVPE. GaN layers with the thickness of 450 nm were characterized using X-ray diffraction. For both, z- and x-cut orientations of LiNbO3 substrates, the GaN layers have c-axis orientation normal to the substrate plane and the in-plane lattice orientation of GaN layers coincides with the primary axes of LiNbO3 substrates. Although GaN layers exhibit almost complete strain relaxation, the residual compressive strain determined with respect to a freestanding GaN is of the order of +0.37% and +0.2% for z- and x-cut substrates, respectively.

Series
PHYSICA STATUS SOLIDI C-CURRENT TOPICS IN SOLID STATE PHYSICS, ISSN 1610-1634 ; Volume: 5, Issue: 6
Keyword
C-axis orientations; Compressive strain; Freestanding GaN; GaN layers; GaN thin films; In-plane lattices; MOVPE; Substrate planes, Gallium nitride; Metallorganic vapor phase epitaxy; Semiconductor growth; Substrates; X ray diffraction, Gallium alloys
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-13703 (URN)10.1002/pssc.200778490 (DOI)000256695700027 ()2-s2.0-50849143992 (Scopus ID)
Conference
7th International Conference on Nitride Semiconductors (ICNS-7), Las Vegas, NV, SEP 16-21, 2007
Note
QC 20100623Available from: 2010-06-23 Created: 2010-06-23 Last updated: 2010-06-23Bibliographically approved
6. Progress on new wide bandgap materials BGaN, BGaAlN and their potential applications
Open this publication in new window or tab >>Progress on new wide bandgap materials BGaN, BGaAlN and their potential applications
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2007 (English)In: Quantum Sensing and Nanophotonic Devices IV / [ed] Razeghi M; Brown GJ, 2007, Vol. 6479, G4791-G4791 p.Conference paper, Published paper (Refereed)
Abstract [en]

The development of wide band gap semiconductors extends their applications in optoelectronics devices to the UV domain. Compact lasers and high sensitivity APD detectors in UV range are currently needed for different applications such as, purification, covert communication and real time detection of airborne pathogens. Until now, the full exploitation of these potential materials has been limited by the lack of suitable GaN substrates. Recently, a novel class of materials has been reported based on BGaN and BAlN, potentially reducing the crystal defect densities by orders of magnitude compared to existing wide band gap heterostructures. Characteristics of these new alloys are similar to those of AlGaN materials with the advantage that these can be lattice matched to AlN and SiC substrates. In addition, these materials offer the possibility of using quaternary BAlGaN alloys at Ultra Violet (UV) wavelengths and hence lead to more degrees of freedom in designing sophisticated device structures. In this paper we describe the MOVPE growth conditions used to incorporate boron in GaN and AlGaN. Detailed characterization and analysis in terms of structural and electrical properties are discussed.

Series
PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE), ISSN 0277-786X ; 6479
Keyword
Electric properties; Energy gap; Heterojunctions; Pathogens; Semiconductor materials; Ultraviolet radiation, Compact lasers; Real time detection; SiC substrates; Ultra Violet (UV) wavelengths, Gallium nitride
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-13671 (URN)10.1117/12.717640 (DOI)000246393600026 ()2-s2.0-34248665565 (Scopus ID)978-0-8194-6592-4 (ISBN)
Conference
Conference on Quantum Sensing and Nanophotonic Devices IV, San Jose, CA, JAN 22-25, 2007, SPIE
Note
QC 20100623Available from: 2010-06-23 Created: 2010-06-23 Last updated: 2010-06-23Bibliographically approved
7. Investigation of intersubband absorption of GaN/AlN multiple quantum wells grown on different substrates by molecular beam epitaxy
Open this publication in new window or tab >>Investigation of intersubband absorption of GaN/AlN multiple quantum wells grown on different substrates by molecular beam epitaxy
Show others...
2007 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 301, no SPEC. ISS., 301-302 p.Article in journal (Refereed) Published
Abstract [en]

Ten period GaN/AlN multiple quantum well (MQW) structures were grown by plasma-assisted molecular beam epitaxy (MBE) on sapphire substrates and metal-organic vapour-phase epitaxy (MOVPE)-grown GaN templates. Samples were investigated by high-resolution X-ray diffraction (HR-XRD) and Fourier transform infrared (FT-IR) spectroscopy. Intersubband (IS) absorbances and FWHM of IS absorption peaks indicated that samples grown on the GaN templates had better characteristics, resulting in a FWHM as low as 93 meV at a peak energy of 700 meV.

Keyword
high-resolution X-ray diffraction, molecular beam epitaxy, quantum wells, nitrides
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-6661 (URN)10.1016/j.jcrysgro.2006.11.258 (DOI)000246015800105 ()2-s2.0-33947321547 (Scopus ID)
Note
QC 20100903Available from: 2006-12-15 Created: 2006-12-15 Last updated: 2010-09-20Bibliographically approved

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