以濺鍍法沉積氮化鎵磊晶薄膜之製程研究

Fabrication Study of GaN Epitaxial Thin Films Prepared by Sputtering Method

廖煜銘(YU-MING LIAO)

指導教授 ： 高慧玲

中原大學/電機資訊學院/電子工程學系/碩士(2022年)

https://doi.org/10.6840/cycu202201160

摘要

本研究以低溫迴旋濺鍍系統，濺鍍砷化鎵靶材，在製程溫度600℃到800℃下成長氮化鎵薄膜在Sapphire及WS2/Sapphire兩種不同基板上。為了確認本研究是否成長出GaN薄膜，先以EDS做成分分析，再以SEM量測薄膜厚度，接著用XRD、TEM對氮化鎵薄膜的品質做進一步分析。
本實驗樣品在EDS確認薄膜內砷含量隨製程溫度上升已降到0%，再來透過SEM確認膜厚，其成長速率高達9nm/min，是過去實驗室成長AlN薄膜之4倍。接著透過XRD量測發現不管是Sapphire或WS2/Sapphire基板在製程溫度高於600℃都具有Ϲ軸從優取向，這點從TEM薄膜選區繞射圖也能證實，不過在明暗場圖中，不管是800℃的GaN/WS2/Sapphire還是GaN/Sapphire都具有大量的差排，推測應與成長速率過快有關。但是具有WS2緩衝層的GaN薄膜，在TEM明暗場、選區繞射圖像中比起沒有緩衝層的GaN薄膜，都有更好的薄膜品質。此外，在TEM選區繞射圖中還發現了局部單晶的現象，證實了通過WS2緩衝層確實可以改善部分原子排列情形，提升薄膜的品質。

關鍵字

砷化鎵靶材 ； 單晶氮化鎵 ； 低溫濺鍍 ； 藍寶石基板 ； 二硫化鎢緩衝層

並列摘要

In this thesis, Gallium Nitride (GaN) thin film have been deposited on two different substates, Sapphire and WS2/Sapphire at low temperatures between 600℃ to 800℃ using helicon sputtering system and Gallium Arsenide (GaAs) target . The film thickness and chemical composition of the films were characterized by SEM and EDS, respectively. XRD was employed to examined the crystallinity of the GaN films, and TEM was used to further investigated the microdefects of the films.
It was found that the arsenic content of the deposited films using GaAs target decreases with the increase of growth temperature. The arsenic concentration in the films was to be 0% as measured by EDS. XRD results show that the films grown on both sapphire and WS2/sapphire substrates exhibit c-axis preferred orientational texture at substrate temperature of 600-800°C. The crystal structure was also confirmed by diffraction pattern of TEM. Although the TEM images of both GaN/Sapphire and GaN/WS2/sapphire prepared at 800°C reveal a large number of dislocations, the GaN film with WS2 buffer layer shows better crystalline quality. In addition, it was found that the film on WS2 exhibits single crystalline from the elected area diffraction pattern, which illustrates that the WS2 buffer layer can indeed play the roll to improve the arrangement of adatoms and improve the quality of the film.

並列關鍵字

GaAs target ； single crystalline GaN ； low-temperature sputtering ； Sapphire substrate ； WS2 buffer layer

參考文獻

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