摘要
深紫外发光二极管(DUV-LED)可广泛应用在杀菌消毒、生化检测、医疗健康和紫外通信等诸多领域。目前商用DUV-LED的电光转换效率通常不足5%,从而使LED发热严重、结温升高,进而导致LED出现峰值波长红移、光衰加剧、寿命缩短等一系列问题。在电光转换效率难以提高的背景下,提升DUV-LED的散热性能以降低其工作结温是十分必要的。热阻是反映LED散热性能的直接参数,其通常受导热面积、材料厚度、材料热导率等因素影响。本文系统研究了DUV-LED的芯片尺寸、焊接层填隙、导热硅脂和基板材质等因素对LED热阻的影响,并对固晶区和焊接层的厚度进行了仿真研究。研究结果表明,增大LED芯片尺寸、对焊接层进行填隙、基板与热沉间涂覆导热硅脂或者将Al基板更换为Cu基板等可以减小LED的热阻。针对商用20 mil×20 mil的275 nm DUV-LED,本研究将其热阻从22.19℃/W降低至12.83℃/W,在25℃环境下,电功率为0.669 W时芯片升温从14.69℃降低至8.49℃。仿真结果表明,LED工作结温随着固晶区或焊接层厚度的减小而线性降低,其中固晶区厚度每增加1 mm,芯片升温将提高44.82℃,因此可以通过适当减薄固晶区厚度来实现热阻的降低。
Deep ultraviolet light-emitting diodes(DUV-LEDs)can be widely used in many fields such as sterilization,biochemical detection,healthcare and UV communication.Currently,the wall-plug efficiency of commercial DUV-LEDs is usually less than 5%,which leads to serious heat generation and high junction temperature,which in turn leads to a series of problems such as peak wavelength redshift,increased light decay,and shortened lifetime of the LEDs.In the context of the difficulty of improving the wall-plug efficiency,it is necessary to improve heat dissipation performance of DUV-LEDs to reduce their operating junction temperature.Thermal resistance is a direct parameter to reflect the heat dissipation performance of LEDs,which is usually affected by factors such as thermal conductive area,material thickness,and material thermal conductivity.In this paper,the effects of chip size,solder gap filling,thermal grease application and PCB materials on the thermal resistance of DUV LEDs have been intensively studied,and the thickness of the solid crystal area and the solder layer have been simulated.It has been found that increasing the size of the LED chip,filling the gap in the solder layer,applying thermal grease and replacing the Al PCB with a Cu PCB can reduce the thermal resistance of the LED.For a commercial 20 mil×20 mil 275 nm DUV-LED,the thermal resistance was reduced from 22.19℃/W to 12.83℃/W,and the chip temperature rise was reduced from 14.69℃to 8.49℃when operating at 25℃and 0.662 W.The simulation results indicate that the LED working junction temperature decreases linearly with the reduction of the thickness of the solid crystal area or solder layer,in which the chip temperature increases by 44.82℃for every 1 mm increase in the thickness of the solid crystal area,so the reduction of thermal resistance can be realized by appropriately thinning the thickness of the solid crystal area.
作者
赵见国
杨佳楠
徐儒
李佳芮
王书昶
张惠国
常建华
ZHAO Jianguo;YANG Jianan;XU Ru;LI Jiarui;WANG Shuchang;ZHANG Huiguo;CHANG Jianhua(School of Electronic and Information Engineering,Nanjing University of Information Science and Technology,Nanjing 210044,China;School of Electronic and Information Engineering,Changshu Institute of Technology,Suzhou 215000,China)
出处
《发光学报》
EI
CAS
CSCD
北大核心
2024年第10期1707-1715,共9页
Chinese Journal of Luminescence
基金
国家自然科学基金(62204121,62005026)。
关键词
深紫外发光二极管
散热性能
热阻
结温
DUV-LED
heat dissipation performance
thermal resistance
junction temperature
