논문 해외 국제전문학술지(SCI급) Precise Temperature Mapping of GaN-Based LEDs by Quantitative Infrared Micro-Thermography
- 학술지 구분 국제전문학술지(SCI급)
- 게재년월 2012-04
- 저자명 김건희
- 학술지명 SENSORS
- 발행처명 MOLECULAR DIVERSITY PRESERVATION INT
- 발행국가 해외
- 논문언어 외국어
- 전체저자수 7
홈페이지논문 초록 (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.