利用原子層沈積技術於藍寶石基板與矽基板上成長氮化鋁薄膜之研究

Study of Aluminum Nitride Thin Films Grown on Sapphire and Silicon Substrates by Atomic Layer Deposition

周宗暐(Tsung-Wei Chou)

指導教授 ： 陳敏璋

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10135

摘要

本論文乃利用原子層沈積技術（Atomic Layer Deposition, ALD）成長氮化鋁薄膜，並分析其各項性質和相關應用。論文可分為三個部分：
第一部分，使用ALD技術於藍寶石基板、矽(100)基板及矽(111)基板上成長氮化鋁薄膜，調整各項製程參數，驗證ALD技術獨特的「自限成膜」機制。利用多種分析技術量測氮化鋁薄膜的各項性質，確認ALD所成長的氮化鋁薄膜為六方晶系纖鋅曠多晶結構，內部缺陷和雜質含量低且表面起伏相當平整，於藍寶石基板上時的薄膜具(002)面c-軸取向性，於矽基板上則無特殊面取向性。
第二部分，分別在氨氣和氮氣兩種不同的氣氛下，對不同基板上使用ALD技術成長的氮化鋁薄膜進行退火熱處理，調整退火溫度及持溫時間，觀察退火熱處理對薄膜各項性質之影響。發現在氨氣氣氛下退火能有效抑制氮原子高溫自表面逸出，因此能獲得較佳品質的氮化鋁薄膜。藍寶石基板上的氮化鋁薄膜於退火後量測發現薄膜的結晶性質和各項性質有明顯改善，且表面粗糙度明顯改變；另一方面，矽基板上的氮化鋁薄膜，因本身取向性不佳，各項性質無明顯改善。
第三部分，使用ALD技術於藍寶石基板上成長氮化鋁薄膜作為緩衝層，施以熱處理後，再進一步使用MOCVD技術成長氮化鎵磊晶層。調整緩衝層厚度及磊晶前退火處理參數，發現氮化鎵磊晶層具有高結晶性及(002)面取向性、低坑洞密度、低載子濃度與高載子遷移率。

關鍵字

原子層沉積技術 ； 氮化鋁 ； 退火熱處理 ； III-族氮化物緩衝層

並列摘要

This thesis investigated the properties and applications of AlN thin films grown by atomic layer deposition (ALD) technique. It can be divided into three main sections:
In the first section, the “self-limiting” behavior of ALD AlN thin films on c-sapphire, Si(100) and Si(111) substrates was observed by adjusting the deposition parameters. The AlN thin films deposited by ALD are poly-cyrstalline of hexagonal wurtzite structure, and the defects density, impurities and surface roughness of AlN thin films are relative low as compared with other growth technique. The AlN films on c-sapphire have (002) c-axis preferred orientation.
In the second part, the effect of annealing on AlN thin films grown by ALD on different substrates was investigated by adjusting the annealing parameters, including the annealing temperature, annealing time, and atmosphere). Significant crystallinity enhancement was achieved under the NH3 atmosphere . The quality of AlN thin films is obviously improved after the annealing treatment without substantially changing the surface roughness and crack formation.
In the last section, the AlN thin films grown by ALD with different thickness and annealing conditions on the c-sapphire substrate as the buffer layers for the MOCVD GaN epitaxy layer With the ALD AlN buffer layer, a good quality GaN epitaxy layer was achieved with high crystallinity of (002) c-axis preferred orientation, low pit density, low carrier concentration, and high carrier mobility.

並列關鍵字

atomic layer deposition(ALD) ； aluminum nitride(AlN) ； thermal annealing ； III-nitrides buffer layer

參考文獻

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