利用雷射剝離與電鍍法研製氮化鎵發光二極體

本實驗主要係利用雷射剝離技術與精密電鍍法製作氮化鎵發光二極體，並探討此一元件特性。我們分別使用Nd-YAG(λ=355nm）與Excimer（λ=248nm）之脈衝雷射束來移除氮化鎵磊晶膜下之藍寶石基板，並藉由精密電鍍法將此氮化鎵磊晶膜轉移至銅基板上以製作氮化鎵發光二極體。這個氮化鎵／銅基板結構的發光二極體顯示比一般傳統的氮化鎵/藍寶石基板結構高出50%的發光強度，而輸出功率也隨著注入的電流呈線性增加，並且分別在180及70毫安培達到飽和，其中，傳統的氮化鎵/藍寶石基板結構發光二極體呈現先達到飽和的狀態，並經由不同電流注入之激發光譜圖，得到氮化鎵/銅基板結構的發光二極體具有較少的波長紅移現象，顯示其在大電流操作下的穩定性，這也顯示經由置換銅基板結構後的氮化鎵發光二極體將有較佳的散熱效果，此即歸因於銅基板有良好的熱傳導係數。

A high-power chip structure of GaN/mirror/Cu light-emitting diodes (LEDs) was developed by a combination of laser lift-off and electroplating techniques. Especially, the LED samples can be accomplished without additional scribing or dicing process. The luminance intensity of the GaN/mirror/Cu LED is about 50% higher than that of the original GaN/sapphire sample. The output power of the GaN/mirror/Cu LED increases linearly with injection current up to 180 mA, while early saturation of the GaN/sapphire device occurs at 70 mA. These indicate that the joule heating is less pronounced for the GaN/mirror/Cu LED sample where the metallic substrate provides a good heat sink.