Femtosecond laser machining of gallium nitride

Kim, T.; Kim, H.S.; Hetterich, M.; Jones, David R.H.; Girkin, John M.; Bente, Eajm Erwin; Dawson, Martin D.

doi:10.1109/leos.2000.893967

Cited by 4 publications

(3 citation statements)

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“…They reported that the pulsed UV vapor copper laser can easily be used for micromachining or dicing of such materials. Kim et al [7] studied the ablation of GaN by ultrashort pulsed laser, and successfully demonstrated the controlled ablation. Nakahama et al [8] used plasma chemical vaporization machining (CVM) to observe the etching characteristics of GaN and reached the conclusion that less subsurface damage is caused by plasma CVM than RIE (reactive ion etching).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Orthogonal Machining of Gallium Nitride via Smoothed Particle Hydrodynamics

Haseeb

Saeed

Ghumman

2022

NIJEC

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Gallium Nitride is one of the best candidates for upcoming industrial revolution due to itssuperior electrical properties over silicon. In the present work, we investigate the chipformation, cutting force and effective stress in diamond machining of gallium nitride bysmoothed particle hydrodynamics approach based on Mohr-Coulomb material model. Thecomparison of the effective stress as reported by molecular dynamics studies and thatpredicted by the smoothed particle hydrodynamics simulation demonstrates the effectivenessof the smoothed particle hydrodynamics model.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Orthogonal Machining of Gallium Nitride via Smoothed Particle Hydrodynamics

Haseeb

Saeed

Ghumman

2022

NIJEC

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“…Pulsed lasers are used to assess recombination dynamics. However, the short pulse duration, low repetition rates excitation lasers used for these measurements often emit pulse powers in the range of MW or even higher, which may result in an irreversible modification of the GaN surface 10 – 12 . Therefore, it is mandatory to study the impact of laser pulses on the integrity of the 3D quantum structures before a detailed characterisation of 3D LEDs, in particular close to the damage threshold.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence of planar and 3D InGaN/GaN LED structures excited with femtosecond laser pulses close to the damage threshold

Jaros

Hartmann

Zhou

et al. 2018

Sci Rep

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We study the photoluminescence emission from planar and 3D InGaN/GaN LED structures, excited using a femtosecond laser with fluences close to sample’s damage threshold. For a typical laser system consisting of a titanium-sapphire regenerative amplifier, which is pumping an optical parametric amplifier delivering output pulses of a few tens of MW pulse power with ∼100 fs pulse duration, 1 kHz repetition rate and a wavelength of 325 nm, we determine the damage threshold of the InGaN/GaN LEDs to be about 0.05 J/cm2. We find that the relative intensity of the GaN photoluminescence (PL) and InGaN PL changes significantly close to the damage threshold. The changes are irreversible once the damage threshold is exceeded. As the damage threshold is approached, the InGaN luminescence band blue-shifts by several tens of meV, which is attributed to band filling effects. The PL decay time reduces substantially, by about 30%, when the excitation energy density is increased by approximately two orders of magnitude. The results are comparable for 2D and 3D LED structures, where in the latter case m-plane QWs exhibit different recombination dynamics because of the absence of the quantum confined Stark effect.

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“…First applications concerned charge carrier lifetime measurements in GaN [6][7][8]. Just after first femtosecond laser machining experiments attempts appeared trying to make trenches in GaN [9,10], a useful method for chip separation. Lots of work has been done using the femtosecond laser machining to increase light extraction from LED's by texturing GaN [11] or its substrate [12][13][14], some includes novel approaches, such as photonic crystal [15] or Fresnel lens [16] structures.…”

Section: Introductionmentioning

confidence: 99%