GaN-based lasers on SiC: influence of mirror reflectivity on L–I characteristics

Schwegler, V.; Schad, Sven‐Silvius; Scherer, M.; Kamp, M.; Ulu, G.; Emsley, M.K.; Ünlü, M. Selim; Lell, A.; Bäder, S.; Hahn, B.; Lugauer, Hans-Juergen; Kühn, F.; Weimar, A.; Härle, V.

doi:10.1016/s0022-0248(01)01299-4

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…[11][12][13][14][15] Of these methods, cleaving has produced the smoothest facet surfaces with root-mean-square (RMS) roughness values on the order of 1 nm for GaN-based laser diodes (LDs) grown on SiC. 3 However, etched facets have a number of advantages, including applicability to laser epilayers grown on substrates such as sapphire that do not have common cleavage planes, and the potential for on-wafer laser testing. Careful manipulation of plasma-etching parameters have led to GaN-based laser facets with RMS roughness values on the order of 20 nm 5 and facet angles ranging from 5 deg to 1 deg from vertical.…”

Section: Introductionmentioning

confidence: 99%

Smooth and Vertical Facet Formation for AlGaN-Based Deep-UV Laser Diodes

Miller

Crawford

Allerman

et al. 2009

Journal of Elec Materi

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Using a two-step method of plasma and wet chemical etching, we demonstrate smooth, vertical facets for use in Al x Ga 1Àx N-based deep-ultraviolet laser-diode heterostructures where x = 0 to 0.5. Optimization of plasma-etching conditions included increasing both temperature and radiofrequency (RF) power to achieve a facet angle of 5 deg from vertical. Subsequent etching in AZ400K developer was investigated to reduce the facet surface roughness and improve facet verticality. The resulting combined processes produced improved facet sidewalls with an average angle of 0.7 deg from vertical and less than 2-nm root-mean-square (RMS) roughness, yielding an estimated reflectivity greater than 95% of that of a perfectly smooth and vertical facet.

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Section: Introductionmentioning

confidence: 99%

Smooth and Vertical Facet Formation for AlGaN-Based Deep-UV Laser Diodes

Miller

Crawford

Allerman

et al. 2009

Journal of Elec Materi

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“…To date, several methods have been employed to fabricate facets for GaN-based near-UV lasers including cleaving, 29,30 milling with focused ion beams (FIB), 31,32 plasma etching, [33][34][35] chemically assisted ion beam etching, 36,37 and two-step processes combining plasma etching or photoenhanced electrochemical etching with wet chemical etching. [38][39][40][41][42] Of these methods, cleaving has produced the smoothest facet surfaces with root mean square (RMS) roughness values on the order of 1 nm for GaN-based laser diodes (LDs) grown on SiC.…”

Section: Processes For High Quality Etched Facetsmentioning

confidence: 99%

“…[38][39][40][41][42] Of these methods, cleaving has produced the smoothest facet surfaces with root mean square (RMS) roughness values on the order of 1 nm for GaN-based laser diodes (LDs) grown on SiC. 30 However, etched facets have a number of advantages, including applicability to laser epilayers grown on substrates such as sapphire, that do not have common cleavage planes, and the potential for on-wafer laser testing. Careful manipulation of plasma-etching parameters have led to GaN-based laser facets with RMS roughness values on the order of 20 nm 5 and facet angles ranging from 5° to 1° from vertical.…”

Section: Processes For High Quality Etched Facetsmentioning

confidence: 99%

Final LDRD report : science-based solutions to achieve high-performance deep-UV laser diodes.

Armstrong¹,

Miller²,

Crawford³

et al. 2011

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We present the results of a three year LDRD project that has focused on overcoming major materials roadblocks to achieving AlGaN-based deep-UV laser diodes. We describe our growth approach to achieving AlGaN templates with greater than ten times reduction of threading dislocations which resulted in greater than seven times enhancement of AlGaN quantum well photoluminescence and 15 times increase in electroluminescence from LED test structures. We describe the application of deep-level optical spectroscopy to AlGaN epilayers to quantify deep level energies and densities and further correlate defect properties with AlGaN luminescence efficiency. We further review our development of p-type short period superlattice structures as an approach to mitigate the high acceptor activation energies in AlGaN alloys. Finally, we describe our laser diode fabrication process, highlighting the development of highly vertical and smooth etched laser facets, as well as characterization of resulting laser heterostructures. 4 ACKNOWLEDGMENTSThe authors gratefully acknowledge Blythe Clark, and Qiming Li for providing assistance in materials characterization. We appreciate the support of managers Dan Barton (project manager), Robert Biefeld, and Jerry Simmons throughout this work.5

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“…Group-III nitride semiconductors and heterostructures have been recognized as belonging to the most promising materials for high-temperature high-power high-electron mobility transistors (HEMTs) [4,5,[89][90][91][92][93][94][95][96][97][98], optoelectronic devices in the short wavelength region (photodetectors and LEDs) [99][100][101][102][103][104][105][106][107], monolithic microwave and optoelectronic integrated circuits [108][109][110][111][112][113][114][115][116][117], heterojunction FETs, MIS-HFETs, MOSFETs , microwave, heterojunction and switched diodes (heterodiodes) [130][131][132][133][134][135][136][137], lasers [109,[138][139][140], as well as other devices, which will have a great impact on the future world [140]. The superior physical and chemical stability of the nitride semiconductors will enable them to operate in harsh en...…”

Section: Gan-and Algan/sic-based Devicesmentioning

confidence: 99%

“…Various technologies have been developed for the reduction of the dislocation density. These approaches include lateral epitaxial overgrowth [137,138] and cantilever epitaxy [149], and significantly reduced dislocation densities in the range 10 6 -10 7 cm −2 have been achieved. Theory [140] and experiment [141] indicate that a further reduction in defect density is possible if the lateral overgrowth approach is extended to the nanoscale.…”

Section: Gan-and Algan/sic-based Devicesmentioning

confidence: 99%

Wide gap semiconductor microwave devices

Buniatyan

Aroutiounian

2007

J. Phys. D: Appl. Phys.

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A review of properties of wide gap semiconductor materials such as diamond, diamond-like carbon films, SiC, GaP, GaN and AlGaN/GaN that are relevant to electronic, optoelectronic and microwave applications is presented.We discuss the latest situation and perspectives based on experimental and theoretical results obtained for wide gap semiconductor devices. Parameters are taken from the literature and from some of our theoretical works. The correspondence between theoretical results and parameters of devices is critically analysed.

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GaN-based lasers on SiC: influence of mirror reflectivity on L–I characteristics

Cited by 4 publications

References 7 publications

Smooth and Vertical Facet Formation for AlGaN-Based Deep-UV Laser Diodes

Smooth and Vertical Facet Formation for AlGaN-Based Deep-UV Laser Diodes

Final LDRD report : science-based solutions to achieve high-performance deep-UV laser diodes.

Wide gap semiconductor microwave devices

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