藉由晶圓接合和雷射剝離技術的搭配將氮化鎵薄膜整合在銅或矽基板上

Abstract

由於缺乏大面積的氮化鎵基板，氮化鎵必須用異質磊晶的方式成長在其它基板上，而目前以藍寶石為最常被使用的基板。不過藍寶石基板在導電性質和導熱性質上是較差的，這對於氮化鎵發光元件之製作與表現給於諸多的難處和限制。幸運的是，透過晶圓接合與雷射剝離基板技術的搭配，可以把氮化鎵薄膜轉移到導電性質和導熱性質較佳的銅基板或矽基板上。 然而在雷射剝離基板的製程中，因應而生的熱應力和壓應力卻成為這個技術最大的挑戰。在研究中發現影響薄膜轉移的均勻性和完整性，最大的關鍵在於氮化鎵薄膜與轉移基板的接合界面上。因此先透過對於晶圓接合的研究，瞭解接合界面的接合機制對於雷射剝離製程的影響，並研究適當的接合技術使氮化鎵薄膜與轉移基板可以均勻而高強度的接合在一起。目前在我們的研究上已經可以很成功的將氮化鎵薄膜均勻而完整的轉移到銅基板上。如此便可以製作上下電極的發光二極體元件，讓氮化鎵發光二極體的製作簡化、並增加發光面積、解決電流散開、使電性和發光效率都有明顯的助益。此外可以用這個技術發展為以銅為基板的氮化鎵雷射二極體、場發射電晶體和異直接面雙極性電晶體，如此可以解決氮化鎵高功率元件散熱的問題，使元件的特性和表現更好。

Due to the lack of a bulk large area GaN substrate, GaN films are growth on other substrates by heteroeptaxial method. And up to now, sapphire is the most used growth substrate. However, sapphire is poor in electrical and thermal conductivity. This could make GaN-based optoelectronic devices difficult and restrict in fabrication and performance. Fortunately, we can transfer GaN films on other substrate that good in electrical and thermal conductivity such as copper or silicon substrate by wafer bonding and laser lift-off technology. However, large thermal and pressure stress would be a big problem during laser lift-off substrate process. In our study, the most influence in films transfer uniform and complete was the interface between GaN film and transfer substrate. So in our experimental will study wafer bonding technology to understand bonded mechanism and to make GaN films bond with transfer substrate uniformly and very strongly. Now, in our study can transfer GaN films on copper substrate very uniformly and completely. In this way, we can fabricate vertical GaN light emitted diode. And we can simplify the light emitted diode fabricate processes, add luminescence area, solve current spreading problem, improve electrical performance, and can get better luminescence efficiency. In addition, we can develop this technique in LD、FET、HBT with copper substrates. In this way we can solve heat sink problem in high power device and would be more useful and excellence in performance.