Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9871
標題: 高密度電漿蝕刻Ⅲ族氮化物及其應用於藍寶石晶圓再生之研究
High-Density-Plasma Etch of Group-Ⅲ Nitrides and Its Application for Sapphire Wafer Reclaim
作者: Lee, Yi-lin
李易霖
關鍵字: 氮化鎵
GaN
感應耦合式電漿
藍寶石
再生晶圓
Inductively Coupled Plasma
Sapphire
Wafer
Reclaim
出版社: 材料工程學研究所
摘要: This thesis describes the etching characteristics of GaN by inductively coupled plasma (ICP) and the effects of process parameters such as ICP source power, rf chuck power, chamber pressure and gas flow rate is investigated. It was found that the ICP power has a large effect on the optimum etch condition, as compared with the other plasma parameters. Pure chlorine gas resulted in the minimum roughness of the reclaimed sapphire surface. For the reclaim of the GaN/sapphire wafer, the initial etch condition (ICP power=1400 W, RF power=150 W, chamber pressure=5 mTorr, and Cl2=30 sccm) was adopted for 5 min, and then switched to another low-etch-rate condition (ICP power=1000 W) until the sapphire surface appeared. It is confirmed that the process developed here can control the surface roughness within 2 nm or below. After the final chemical-mechanical polishing, the roughness of the sapphire surface can be controlled within 1 nm below, which meet the reclaimed sapphire specification. In order to demonstrate the quality of the reclaimed sapphire wafer, the GaN epilayers were simultaneously grown on the original and reclaimed sapphire wafers. From photoluminescence (PL) mapping results, both wafers show very small difference in PL quality. After etching, the dislocation density for the GaN epilayers grown on the original and reclaimed sapphire wafers was determined to be 3.8109 and 2.8109 cm-2. These results indicate the etching process developed can be applied for the reclaim of GaN/sapphire wafers.
本論文為探討在感應耦合式電漿(ICP)系統中,藉由改變腔體壓力、上電極功率、下電極射頻功率以及氣體流量等參數的改變,來研究蝕刻氮化鎵時的效應。探討如何改變ICP之參數以得到最佳蝕刻的效果。其中我們選用氣體為氯氣,如果使用其他添他氣體的話,會增加表面粗糙度的變大。初始蝕刻條件:ICP power=1400 W、RF power=150 W、壓力為5 mTorr及使用30 sccm的氯氣,這樣蝕刻約5分鐘,再改變上電極功率為1000 W,其餘參數維持固定,蝕刻至藍寶石上的磊晶膜完全被去除為止。這種方法可以縮短蝕刻時間,而在把上電極功率降低時,可使藍寶石表面的粗糙度控制在2 nm以下。然後再經由拋光後,可使再生之藍寶石晶圓的粗糙度控制在1 nm以下,跟新晶圓所要求的粗糙度是相符合的。 我們把蝕刻氮化鎵的技術應用於藍寶石晶圓再生上磊晶層(GaN) 之蝕刻,這樣可以降低蝕刻後藍寶石的表面傷害。為了證明再生藍寶石晶圓的可行性,我們把再生藍寶石晶圓去成長氮化鎵薄膜,而氮化鎵薄膜之光學特性和磊晶品質分別使用光激發光譜和場發射掃描式電子顯微鏡加以分析。藉由實驗結果分析,再生藍寶石晶圓的確有其可行性,由光激發光譜量測可知再生晶圓與原始全新晶圓上之氮化鎵的光強度與半高寬高值差異不太。由場發射掃瞄式電子顯微鏡可觀察濕式蝕刻後原始全新晶圓與再生晶圓上之氮化鎵之蝕刻缺陷密度值約為3.8×109 cm-2與2.8×109 cm-2,差排密度並無明顯之差異。
URI: http://hdl.handle.net/11455/9871
Appears in Collections:材料科學與工程學系

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