KrF excimer laser induced ablation–planarization of GaN surface

Akane, Toshimitsu; Sugioka, Koji; Ogino, Hirotaka; Midorikawa, Katsumi

doi:10.1016/s0169-4332(99)00156-7

Cited by 28 publications

(11 citation statements)

References 11 publications

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“…One of the side-effects of laser ablation is the formation of sedimentary by-products on the surface of GaN [8]. These substances were effectively removed by sonifying the sample in dilute hydrochloric acid (HCl) (18% by mass) for 15 minutes.…”

Section: Methodsmentioning

confidence: 99%

Deep etch of GaN by laser micromachining

Mak

Lam

Choi

2010

Phys. Status Solidi (c)

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Trench formation for device isolation on GaN light‐emitting diode (LED) wafers via nanosecond ultraviolet laser micromachining is demonstrated. Owing to the dissimilar ablation thresholds between GaN and sapphire, the etch process terminates automatically at the GaN/sapphire interface. It was found that optimal focus offset, optimal pulse energy and high repetition rate are essential for obtaining a trench with tapered sidewall and smooth bottom surface, which is suitable for the conformal deposition of interconnects across the trench. This technique has been successfully applied to the rapid prototyping of interconnected LED arrays on a single chip. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Methodsmentioning

confidence: 99%

Deep etch of GaN by laser micromachining

Mak

Lam

Choi

2010

Phys. Status Solidi (c)

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“…A charge-coupled device (CCD) camera was installed confocal to the optical path for real-time observation of the micromachining process. Owing to the high temperature during laser ablation, sedimentary by-products were formed on the surface of GaN, such as Ga metal (Akane, et al 1999b;Kelly, et al 1996) and gallium oxide (Gu, et al 2006). These substances were effectively removed by sonification of the sample in dilute hydrochloric acid (HCl) (18% by mass) for 15 min.…”

Section: Trench Micromachining In Airmentioning

confidence: 99%

Laser Micromachining and Micro-Patterning with a Nanosecond UV Laser

Wang¹,

Mak²,

Choi³

2012

Micromachining Techniques for Fabrication of Micro and Nano Structures

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“…Some recent investigations have indicated that such a process is feasible through the laser-induced thermal decomposition of the GaN surface. It has been demonstrated that the irradiation with several pulses of a KrF [2,3] and a F2 [4] lasers could lead to a significant planarization of GaN films grown on sapphire. The maximum effect, a reduction from the initial roughness of 0s = 1 0 nm to 2 nm, was observed for the 7-pulse KrF laser irradiation at the fluence of F 1 J/cm2 per pulse (i; = 34 ns) [3].…”

Section: Introductionmentioning

confidence: 99%

<title>Laser polishing of GaN</title>

et al. 2001

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The ablative decomposition of GaN films induced with a XeC1 excimer laser (? = 308 nm) was investigated for a potentially low-damage surface planarization process. Samples, 2-tm-thick, were grown on (0001) sapphire by ammonia molecular beam epitaxy. They had a characteristic micro-hillock type surface morphology with a roughness, averaged over 5 x 5 tm2 area, typically, of 13 nm. Following the laser irradiation, this roughness could be reduced to 3.6 urn. The results indicate that the ablation process follows the Lambert-Beer's law, with an absorption coefficient of 3 x iO cm'. The experiment was carried out with relatively short pulses ('r =10 ns), which appear to be responsible for the observed onset of the laser-induced decomposition of GaN and surface planarization at significantly smaller laser fluences than reported in the literature. The ability to carry out decomposition of GaN with low laser fluences is of practical importance for achieving a low-damage GaN planarization process and/or intentional delaminating of this material from the sapphire substrate by the back side irradiation technique.

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KrF excimer laser induced ablation–planarization of GaN surface

Cited by 28 publications

References 11 publications

Deep etch of GaN by laser micromachining

Deep etch of GaN by laser micromachining

Laser Micromachining and Micro-Patterning with a Nanosecond UV Laser

<title>Laser polishing of GaN</title>

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