Thermal analysis of GaN‐based LEDs using the finite element method and unit temperature profile approach

Lee, Tae Hee; Kim, Lan; Hwang, Woong Joon; Lee, C. C.; Shin, Moo Whan

doi:10.1002/pssb.200405099

Cited by 16 publications

(5 citation statements)

References 3 publications

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“…3, thermal resistance changes are due to different cooling mechanism. In the convection mechanism, heat dissipation efficiency mainly depends on the heat transfer coefficient, h [9]. The coefficient, h, is increased when the input current is increased and the junction temperature rises.…”

Section: Resultsmentioning

confidence: 99%

Thermal analysis of GaN‐based laser diode package

Hwang

Lee

Nam

et al. 2006

Phys. Status Solidi (c)

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This paper reports on the thermal behavior of GaN-based laser diode (LD) package as functions of cooling systems, die attaching materials, and chip loading conditions. Thermal resistance and junction temperature was determined by electrical-thermal transient method. Significant change of thermal resistance with input current was observed under natural cooling condition due to the sensitive change of heat transfer coefficient (h) with temperature. Employment of PbSn as a die attachment was more advantageous over Ag-paste in thermal behavior of LD package. Compare the thermal resistance of LD packages epidown and epi-up structures. The partial thermal resistance from junction to submount is 4.68 K/W for epidown structure, and 9.65 K/W to epi-up structure. The results demonstrate that the total thermal resistance of LD package be controlled mainly by the packaging design rather than the chip structure itself.1 Introduction GaN-based blue laser diode (LD) is of significant importance for the applications such as optical data storage and communication system. It is well documented that the performances of LD products can be improved with higher laser power [1, 2]. However, high power operation leads to high junction temperature. High junction temperature degrades the optical performance, thus causes potential device failure and reliability problem [3,4]. Therefore, accurate and reliable characterization of thermal behavior is very important for the development of LD packages with a long-life time. The thermal resistance in the most useful indicator of thermal performance of LD package. The thermal resistance is defined as the ratio between the temperature difference between the junction and the ambient and dissipated power [5]. The thermal resistance is a direct indicator how much heat is generated under certain input power in the p-n junction, and it becomes a prime interest to package designers of high power GaN-based LD.In this paper thermal analysis was performed for different cooling system and structures of GaN LD packages. Thermal transient technique was employed for the investigation of thermal behavior. Thermal resistance was measured under forced cooling system and natural cooling system for samples with epi-up and epi-down structures. Thermal analysis was performed as a function of submount materials as well. The thermal resistance represents the contribution from each different layers of heat transfer path in LD structure. By this way, we investigated the thermal behavior as functions of input current and package structure of GaN-based LD package.

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Section: Resultsmentioning

confidence: 99%

Thermal analysis of GaN‐based laser diode package

Hwang

Lee

Nam

et al. 2006

Phys. Status Solidi (c)

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“…In the convection mechanism, the heat dissipation efficiency mainly depends on the heat transfer coefficient, . The coefficient, , increased when the input current is increased and the junction temperature increased [12]. The relationship between the temperature and can be expressed as follows:…”

Section: Resultsmentioning

confidence: 99%

Thermal Investigation of GaN-Based Laser Diode Package

Hwang

Lee²,

Choi

et al. 2007

IEEE Trans. Comp. Packag. Technol.

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We investigated thermal behavior of GaN-based laser diode (LD) packages as a function of cooling systems, die attaching materials, chip loading conditions, and optical performances. The electrical thermal transient technique was employed for the thermal measurement of junction temperature and thermal resistance of LD packages. The results demonstrate that the total thermal resistance of LD packages is controlled mainly by the packaging design rather than the chip structure itself. Significant changes in thermal resistance with input current were observed under a natural cooling system because of the sensitive change in the heat transfer coefficient with the change in temperature. Employment of PbSn as a die attachment was more advantageous over the Ag-paste in the thermal behavior of LD packages. The LD package with epi-down structure resulted in the lower thermal resistance compared to one with epi-up structure. A continuous increase in junction temperature was measured after lasing. It was attributed to an increase in the thermal resistance of LD when it took the optical power into an account. Effective input power was decreased by the lasing and led to high thermal resistance values.Index Terms-Die bonding, GaN, heat transfer coefficient, laser diode (LD) package, optical power, structure functions, thermal resistance, thermal transient measurement.

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“…The finite element method (FEM) can be used to simulated thermal characteristics for LEDs 18 in ANSYS, a well-established simulation program widely used for mechanical and electrical problems. Its capabilities include a combined thermal-electrical solver employing all linear effects and non-linear thermal transport properties.…”

Section: Experiments and Simulation For Light-emitting Diode Sourcementioning

confidence: 99%

Optical design and thermal analysis of high-power light-emitting diode array modules

Dai¹,

Chen

2012

SIMULATION

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In this paper, the optical-thermal characteristics for single-power light-emitting diodes (LEDs) are firstly studied based on experiment and theory, with both results in good agreement. Based on the results of single-power LED, an optical system is proposed with thermal-optical LED array modules, which are assembled upon a spherical base plate with heat sink. By simulation, the optical system is proved to provide uniform illumination. The luminance uniformity of the illuminated target is up to 0.9. The thermal effects under different heat convection coefficient and power consumption on the LED array modules are discussed in detail. Based on the heat transfer characteristics for the LED system, the approximate allowable power consumption for modules can be found.

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Thermal analysis of GaN‐based LEDs using the finite element method and unit temperature profile approach

Cited by 16 publications

References 3 publications

Thermal analysis of GaN‐based laser diode package

Thermal analysis of GaN‐based laser diode package

Thermal Investigation of GaN-Based Laser Diode Package

Optical design and thermal analysis of high-power light-emitting diode array modules

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