Location of Repository

Precise Temperature Mapping of GaN-Based LEDs by Quantitative Infrared Micro-Thermography

By Ki Soo Chang, Sun Choel Yang, Jae-Young Kim, Myung Ho Kook, Seon Young Ryu, Hae Young Choi and Geon Hee Kim

Abstract

A method of measuring the precise temperature distribution of GaN-based light-emitting diodes (LEDs) by quantitative infrared micro-thermography is reported. To reduce the calibration error, the same measuring conditions were used for both calibration and thermal imaging; calibration was conducted on a highly emissive black-painted area on a dummy sapphire wafer loaded near the LED wafer on a thermoelectric cooler mount. We used infrared thermal radiation images of the black-painted area on the dummy wafer and an unbiased LED wafer at two different temperatures to determine the factors that degrade the accuracy of temperature measurement, i.e., the non-uniform response of the instrument, superimposed offset radiation, reflected radiation, and emissivity map of the LED surface. By correcting these factors from the measured infrared thermal radiation images of biased LEDs, we determined a precise absolute temperature image. Consequently, we could observe from where the local self-heat emerges and how it distributes on the emitting area of the LEDs. The experimental results demonstrated that highly localized self-heating and a remarkable temperature gradient, which are detrimental to LED performance and reliability, arise near the p-contact edge of the LED surface at high injection levels owing to the current crowding effect

Topics: Article
Publisher: Molecular Diversity Preservation International (MDPI)
OAI identifier: oai:pubmedcentral.nih.gov:3355432
Provided by: PubMed Central
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://www.pubmedcentral.nih.g... (external link)
  • Suggested articles

    Preview

    Citations

    1. (2005). Analysis of thermal images from diode lasers: Temperature profiling and reliability screening.
    2. (2006). Application of an IR thermographic device for the detection of a simulated defect in a pipe. Sensors
    3. (2001). Current crowding and optical saturation effects in GaInN/GaN light-emitting diodes grown on insulating substrates.
    4. (2001). Current crowding in GaN/InGaN light emitting diodes on insulating substrates.
    5. (2007). Current spreading and thermal effects in blue LED dice.
    6. (2010). Degradation mechanism of light-emitting diodes on patterned sapphire substrate.
    7. (2006). Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN/GaN LEDs. Semiconductors
    8. (2004). High spatial resolution subsurface thermal emission microscopy.
    9. (2002). Illumination with solid state lighting technology.
    10. (2009). In situ measurement of the junction temperature of light emitting diodes using a flexible micro temperature sensor. Sensors
    11. (2007). Infrared microthermography of microfabricated devices.
    12. (2008). Junction temperature measurements and thermal modeling of GaInN/GaN quantum well light-emitting diodes.
    13. (2010). Junction temperature, spectral shift, and efficiency in GaInN-based blue and green light emitting diodes. Thin Solid Films
    14. (2004). Junction-temperature measurement in GaN ultraviolet light-emitting diodes using diode forward voltage method.
    15. (2004). Measurement of temperature profiles on visible light-emitting diodes by use of a nematic liquid crystal and an infrared
    16. (2009). Microthermography of diode lasers: The impact of light propagation on image formation.
    17. (2005). Solid-state light sources getting smart. Science
    18. Status and future of high-power light-emitting diodes for solid-state lighting.
    19. (2012). Study on high-precision temperature measurement of infrared imager.
    20. (2011). Thermal imaging of encapsulated LEDs.
    21. Thermal infrared emission from biased grapheme.

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.