- 學位論文
應用高導熱膜層於高功率發光二極體散熱效果之研究
Study of heat transfer effect of high power LEDs by high heat conduction layer
摘要
發光二極體具有節能、環保、壽命長等優點。目前發光二極體的電光轉換效率只有大約 15〜25％，其餘的電能在PN接面處產生熱能。因此，隨著發光二極體的輸入功率越高，PN接面處產生的熱能越高。為了避免LED過熱，必須採用高導熱膜層來提升基板的熱傳導率。例如鑽石(DLC)薄膜或氮化鋁(AlN)薄膜等。 本研究分為三個階段，第一階段為研究鑽石(Diamond)薄膜的成長機制，使用熱燈絲化學氣相沉積系統(HFCVD)，沉積鑽石薄膜在矽基板上。第二階段為研究氮化鋁薄膜的特性，使用反應性濺鍍(Reactive Sputtering)系統，沉積氮化鋁薄膜在矽基板上。第三階段是熱阻量測與分析，第一部份量測LED整體含基板的熱阻，DLC薄膜約59.28 (℃/W)，AlN薄膜約69.05 (℃/W)，而矽基板約80.97 (℃/W)，第二部份為基板的熱阻，從實驗結果得知，DLC薄膜約3.57 (℃/W)，AlN薄膜約5.9 (℃/W)，矽基板約10.23 (℃/W)。由上述的量測結果得知，熱阻最低的是DLC薄膜，且接面溫度最低的也是DLC薄膜，這證明DLC薄膜能有助於LED散熱，且熱消散效果最好。
並列摘要
The advantages of light emitting diodes(LEDs) are the power saving, environment friendly, and long lifetime. So far the optical efficiency of LED is only about 15~25%, the rest electrons and holes cause heat at p-n junction. Consequently, the main problem of high power LEDs is the generated heat at p-n junction. In order to avoid LED chips from overheating, the high heat conduction layers should be used to increase the thermal conductivity of substrate. For example, diamond-like carbon films (DLC) or aluminum nitride films (AlN). This dissertation was divided into three parts. Firstly, the growth mechanism of diamond-like carbon films was studied. The diamond-like carbon films were deposited on silicon substrates by using hot filament chemical vapor deposition (HFCVD). The second part is to study the properties of Aluminum nitride thin films. The Aluminum nitride films were deposited on silicon substrates by reactive sputtering system. The third part is the thermal resistance measurement and analysis. The overall thermal resistances were measured from p-n junction to substrate. Measured thermal resistance of DLC films, AlN film, and the silicon substrate are about 59.28 (℃/W), 69.05 (℃/W), and 80.97 (℃/W), respectively. Excluding the effect of LED and submount, i.e. the thermal resistances of the conduction films in series with substrate were measured. From the experimental results, the thermal resistances of DLC films, AlN films, and silicon substrate are about 3.57 (℃/W), 5.9 (℃/W), and 10.23 (℃/W), respectively. From the above results, the lowest thermal resistance was found by using the DLC films, such that the junction temperature of p-n junction was also the lowest value. This is the evidence that DLC films has good thermal dissipation effect.