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

Sensors

Ki Soo Chang¹  Sun Choel Yang¹  Jae-Young Kim¹  Myung Ho Kook¹  Seon Young Ryu¹  Hae Young Choi² 

[1] Division of Instrument Development, Korea Basic Science Institute, Daejeon 305-333, Korea; E-Mails:;Medical Device Development, Osong Medical Innovation Foundation, Chungbuk 363-951, Korea; E-Mail:

关键词: infrared;    thermography;    light-emitting diode (LED);    temperature;   

DOI  :  10.3390/s120404648

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.