化學機械研磨法之垂直結構發光二極體

Abstract

摘要

目前GaN 發光二極體主要採用藍寶石作為基板。藍寶石是絕緣體而且不具有良好的熱傳導性，從而限制了大功率發光二極體的發展。本論文設計了一種全新的垂直結構發光二級體的製作工藝。 本論文提出了一種全新的藍寶石基板移除方法，即採用化學機械研磨(Chemical Mechanical Polishing, CMP)的方法。通過引入研磨阻止層製程，本論文實現了穩定重復藍寶石基板移除。在此基礎上，本論文將氮化鎵薄膜移轉至導電性導熱性較佳的銅基板上，並製作出了垂直結構發光二極體樣品。本論文測試了相關樣品的光電特性，現階段的樣品仍然存在正向電壓高的問題，但是樣品的反向電特性正常。樣品的發光亮度也需要進一步提升。

ABSTRACT Currently most of the GaN light emitting diode(LED) use sapphire as substrate. However sapphire is an insulator and is not a good conductor of heat. All these properties limit the progress of high power LED. Hence in this article we design a novel process of vertical structure LED for high power purpose. In this article, we propose a novel method to remove sapphire which is using chemical mechanical polishing (CMP). By introducing polishing stop layer, we succeed in removing sapphire substrate. This is result is reproducible. From this results, this article transfer the GaN LED on copper substrate and produce the vertical structure LED. The prototype is tested for electrical and optical properties. The forward voltage of the prototype is high and need to be further optimized. The reverse properties of the prototype is good. The light output of the prototype also needs to be optimized further.