Measurement of mounting-induced strain and defects in high-power laser diodes using Fourier-transform photo-current spectroscopy

Gerhardt, A.; Tomm, Jens W.; Müller, Roland; Bärwolff, A.; Lorenzen, Dirk; Donecker, J.

doi:10.1016/s0921-5107(01)01007-8

Cited by 4 publications

(1 citation statement)

References 6 publications

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“…Minimizing this stress improves the operating life of the device. Various stress-mapping measurement techniques [64][65][66][67][68] have been proposed to study the effect of stress on its operational parameters such as spectral position and polarization [69], [70] as well as lifetime and reliability [71], [72]. Localized stress distribution in the LD can be monitored by using photoluminescence technique.…”

Section: Stress Considerationsmentioning

confidence: 99%

Study and development of advanced packaging technique for semiconductor lasers

Teo¹

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The development of Erbium-Doped Fiber Amplifiers (EDFA) in long-haul telecommunications applications resulted in the rapid evolution of high power semiconductor lasers. In these applications, the demand for increased channel density in fiber-optic communication has pushed forward the use of single-mode ridge-waveguide laser diodes (LDs). One of the major concerns in these single-mode LD packages is the thermal management of the module. These semiconductor lasers usually generate large heat fluxes, up to the range of MWcm" 2 , that adversely affect their performance and reliability. Thus, the aim of packaging is to dissipate heat as efficiently as possible, in order to operate the LD at its maximum optical performance, without exceeding the permitted device temperature. As a first stage packaging, die-attachment of LDs onto a submount/heatsink is adopted and face-down bonding approach is recommended to meet the large heat generation rate. Some of the packaging-related issues faced in this bonding configuration are precision bonding alignment, low bonding yield, high bonding stress, good bonding integrity, as well as long-term reliability issues. This thesis introduces the development of a modified bonding technique for single-mode ridge-waveguide LDs. The effects of bonding parameters on the microstructure, bonding integrity of the solder joint, and LD performances were analyzed. Reliability tests such as thermal cycling and accelerated aging tests were also performed to prove the package's long-term stability. The solder joint possessed good long-term reliability, with little intermetallic compounds (IMC) growth at the interfaces. The formation of Au-rich P and i ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library CJ phase Au/Sn compounds in the solder joint limit the interfacial IMC growth. Mechanical testing exhibited excellent bonding integrity, with brittle fracture occurring within the LD. No degradation of threshold current I t h could be observed and a 3X optical improvement over unbonded LDs was attained due to improved thermal management. Band structure theory of semiconductor lasers was conducted to understand the temperature-dependence characteristics of LDs. Transient and steady-state thermal analysis of semiconductor lasers showed that the heat generated in the LD and its associated thermal resistance R t h was induced by the radiative energy transfer of free carriers. The dependence of R t h on different bonding configurations and its correlation with the output power was discussed. Finite Element (FE) modeling was also carried out to provide theoretical understanding on the temperature distribution and thermal dissipation for different bonding configurations. Face-down bonded LDs demonstrated improved thermal management with-80% of heat flow towards the heatsink while faceup bonded LDs could only manage-50%. The analytical method using electronic band structure calculations and FE modeling gave close fitting to the experimental result...

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Section: Stress Considerationsmentioning

confidence: 99%

Study and development of advanced packaging technique for semiconductor lasers

Teo¹

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The impact of temperature and strain-induced band gap variations on current competition and emitter power in laser bars

Amuzuvi

Bull

Tomm

et al. 2011

Applied Physics Letters

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We report on current competition and emitter power distributions of unaged 650 nm red-emitting and 980 nm infrared tapered high-power laser bars. We observe a correlation between temperature and packaging-induced strain with respect to the emitter output power. A frown-shaped profile of the output power distribution is seen when the temperatures of the emitters near the center of the bar increase compared to those at the edges of the bar. The effect of temperature is found to dominate that of strain and therefore determine the output power distribution across the bar.

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Effect of uniaxial stress on electroluminescence, valence band modification, optical gain, and polarization modes in tensile strained p-AlGaAs/GaAsP/n-AlGaAs laser diode structures: Numerical calculations and experimental results

Богданов

Minina

Tomm

et al. 2012

Journal of Applied Physics

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Efficient, narrow linewidth excitonic emission at room temperature from GaAs/AlGaAs V-groove quantum wire light-emitting diodesThe effects of uniaxial compression in [110] direction on energy-band structures, heavy and light hole mixing, optical matrix elements, and gain in laser diodes with "light hole up" configuration of valence band levels in GaAsP quantum wells with different widths and phosphorus contents are numerically calculated. The development of light and heavy hole mixing caused by symmetry lowering and converging behavior of light and heavy hole levels in such quantum wells under uniaxial compression is displayed. The light or heavy hole nature of each level is established for all considered values of uniaxial stress. The results of optical gain calculations for TM and TE polarization modes show that uniaxial compression leads to a significant increase of the TE mode and a minor decrease of the TM mode. Electroluminescence experiments were performed under uniaxial compression up to 5 kbar at 77 K on a model laser diode structure (pÀAl x Ga 1Àx As= GaAs 1Ày P y =nÀAl x Ga 1Àx As) with y ¼ 0.16 and a quantum well width of 14 nm. They reveal a maximum blue shift of 27 meV of the electroluminescence spectra that is well described by the calculated change of the optical gap and the increase of the intensity being referred to a TE mode enhancement. Numerical calculations and electroluminescence data indicate that uniaxial compression may be used for a moderate wavelength and TM/TE intensity ratio tuning. V C 2012 American Institute of Physics. [http://dx.

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Measurement of mounting-induced strain and defects in high-power laser diodes using Fourier-transform photo-current spectroscopy

Cited by 4 publications

References 6 publications

Study and development of advanced packaging technique for semiconductor lasers

Study and development of advanced packaging technique for semiconductor lasers

The impact of temperature and strain-induced band gap variations on current competition and emitter power in laser bars

Effect of uniaxial stress on electroluminescence, valence band modification, optical gain, and polarization modes in tensile strained p-AlGaAs/GaAsP/n-AlGaAs laser diode structures: Numerical calculations and experimental results

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