深紫外發光二極體之電熱特性及可靠度研究

The Investigation of Electrothermal Characteristics on long-term Reliability of Deep Ultraviolet Light-Emitting Diodes

陳彥廷(Yen-Ting Chen)

指導教授 ： 王建評

中原大學/工學院/機械工程研究所/碩士(2018年)

https://doi.org/10.6840/cycu201800458

摘要

本研究主要探討由LG Innotek公司所製作的深紫外光發光二極體，研究其電熱特性及可靠度測試，分析輸入不同之操作電流及不同環境溫度下，電壓與輻射通量之變化，並且藉由熱結構函數計算出深紫外光發光二極體之熱阻值，同時以紅外線熱像儀拍攝樣品表面溫度，藉此觀測樣品表面在各個條件下的溫度變化，最終藉由老化試驗分析此深紫外光發光二極體之可靠度，於此實驗中記錄其電熱特性隨點量時間之變化量。
本研究之可靠度試驗探討參數為:50mA、100mA、150mA三種不同的操作電流以及25℃、35℃、45℃、55℃四種不同的環境溫度，經過1000小時老化試驗後可以發現在相同的環境溫度下，操作電流較高者對於輻射通量之衰退較為顯著。相同操作電流下，環境溫度較高者對於輻射通量之衰退也較為顯著。將可靠度試驗參數透過熱阻值量測後皆可以轉換成接面溫度，可以發現環境溫度為25℃且操作電流為150mA時接面溫度為54.886℃，環境溫度為55℃且操作電流為50mA時接面溫度為62.517℃，兩者在老化1000小時輻射通量衰退至原先的68.74%和73.95%，後者有較高的接面溫度但在輻射通量衰退卻較低，於過往文獻有將衰退機制分為電應力及熱應力兩類，探討環境溫度與操作電流對於可靠度之影響，最終顯示操作電流所造成的衰退比環境溫度所造成的衰退較為顯著，電應力對於其可靠度之影響較為顯著。

關鍵字

深紫外發光二極體 ； 可靠度 ； 輻射通量 ； 熱阻

並列摘要

The present study investigates both electrothermal characteristics and reliability of the deep ultraviolet light-emitting diodes made by LG Innotek. The variations of voltage and radiation flux at different input currents and ambient temperatures are analyzed. The thermal resistance values of the deep ultraviolet light-emitting diodes are calculated by the thermal structure functions. Observing the surface temperature change of the deep ultraviolet light emitting diode with the infrared camera, and finally analyzing the reliability of the deep ultraviolet light emitting diode by the aging experiment.
The reliability test of this study explores three different operating currents of 50 mA, 100 mA, and 150 mA, and four different ambient temperatures of 25℃, 35℃, 45 ℃, and 55℃. After 1000 hours of aging test, the higher operating current is more significant for the decline of radiant flux at the same ambient temperature. The higher ambient temperature is also more significant for the decline of radiant flux under the same operating current. The parameter of the reliability test is measured by the thermal resistance, it can be converted into the junction temperature. It can be found that the junction temperature is 54.886℃ under the operating current is 150 mA and the ambient temperature is 25℃,and the junction temperature is 62.517℃ under the operating current is 50 mA and the ambient temperature is 55℃. The radiant flux of the two under the 1000 hours of aging deteriorated to the original 68.74% and 73.95%. The latter has a higher junction temperature but a lower radiant flux decline. In the past, the degradation mechanism was divided into electrically stressed and thermally stressed. Finally, the degradation caused by operating current is more significant than the ambient temperature. The influence of electrical stress on its reliability is significant.

並列關鍵字

UVC LED ； reliability ； radiant flux ； thermal resistance

參考文獻

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