本實驗室參與雷射干涉重力波偵測天文台組織(Laser Interferometer Gravitational-Wave Observatory, LIGO)之研究計畫，使用超大型麥克森干涉儀去偵測重力波，但因為重力波的訊號非常小，容易受到各種雜訊所干擾，在100Hz左右最靈敏的偵測頻率區間，其所主導的雜訊來源為高反射鏡上薄膜的熱擾動雜訊(coating Brownian Noise)，而根據fluctuation-dissipation theorem可知道熱擾動雜訊與機械損耗成正比，因此本研究改良可應用於LPCVD之單晶矽懸臂來進行低溫機械損耗的量測。
本實驗室先前已利用電漿輔助式化學氣相沈積法(Plasma Enhanced Chemical Vapor Deposition, PECVD)鍍製氮化矽薄膜材料，並且發現薄膜的光學吸收與薄膜內的N-H鍵和Si-鍵濃度有關，因此為了使薄膜的光學吸收再降低，本實驗室蔡東霖同學開發使用低壓化學氣相沉積法(Low Pressure Chemical Vapor Deposition, LPCVD)鍍製不同製程氣體SiH2Cl2/ NH3流量比的氮化矽薄膜，藉由高溫製程環境降低薄膜內的N-H鍵結含量，達到降低光學吸收的效果。而本研究延續其實驗內容，針對低SiH2Cl2/ NH3流量比的氮化矽薄膜材料，透過高溫純氮退火的製程方式，將薄膜內的N-H鍵斷鍵，在Si-鍵濃度不增加太多的狀況下，可使得薄膜的光學吸收再降低。本研究透過改變退火溫度以及增加退火時間的方式，找到擁有最佳光學吸收的氮化矽薄膜材料。
根據本實驗結果，對SiH2Cl2/ NH3流量比為1的氮化矽薄膜材料進行1000℃退火1.5小時後，其在1550nm波長下的光學吸收數值，由未退火時的6.1×10^(-6)降低至1.3×10^(-6)，降幅約78%；而在1950nm波長下的光學吸收值由2.5×10^(-5)降低至5.8×10^(-6)，降幅約76%。此外，由本實驗室先前之研究結果顯示，薄膜的低溫機械損耗與其N-H鍵結含量呈正相關，所以經過高溫退火後的氮化矽薄膜，不但在光學吸收上有非常優秀的表現，在低溫機械損耗的上也期待會有不錯的結果，可以被期待作為下個世代低溫重力波偵測儀的高反射鏡鍍膜材料。

Our laboratory participates in the research project of the Laser Interferometer Gravitational-Wave Observatory (LIGO), which uses a super-large Michelson interferometer to detect gravitational waves. The gravitational wave signals are very weak and easy to be affected by various noises. The dominant noise source in the most sensitive detection frequency range around 100Hz, is the thermal disturbance noise (coating Brownian noise) of the thin film on the high-reflective mirror. According to the fluctuation-dissipation theorem, it can be known that the thermal disturbance noise is proportional to the mechanical loss. In this study, we improved the silicon cantilever system, which can be applied to LPCVD, to measure low-temperature mechanical loss.
Our laboratory has previously used Plasma Enhanced Chemical Vapor Deposition (PECVD) to coat silicon nitride thin films and found that the optical absorption of thin films is related to the concentration of N-H bonds and Si-bonds in the films. To reduce the optical absorption of the film, Dong-Lin Tsai uses low pressure chemical vapor deposition (LPCVD) to coat silicon nitride films with different process gas flow ratios. The high temperature process environment reduces the N-H bond content in the film and greatly decreases optical absorption. Following his experimental results, for the silicon nitride thin film material with low SiH2Cl2/NH3 flow ratios, to use the high-temperature annealing process to break the N-H bond in the film, so that the optical absorption of the film can be further reduced. In this study, by changing the annealing temperature and increasing the annealing time, the silicon nitride film material with the best optical absorption was found.
According to the results of this study, after annealing the silicon nitride thin film material with SiH2Cl2/NH3 flow ratio of one at 1000℃ for 1.5 hours, its optical absorption value at 1550nm wavelength decreases from 6.1×10^(-6) to 1.3×10^(-6), and the decrease is about 78%; the optical absorption value at 1950nm wavelength decreased from 2.5×10^(-5) to 5.8×10^(-6), a decrease is about 76%. In addition, the low-temperature mechanical loss of the film is positively related to its N-H bond content, hence the silicon nitride film after high-temperature annealing not only has excellent performance in optical absorption, but is also expected to have excellent results in low-temperature mechanical loss. It has the potential to be used as a high-reflective mirror coating material for the next generation of low-temperature gravitational wave detectors.

Abstract i
摘要 iii
致謝 v
目錄 vii
圖目錄 x
表目錄 xiii
第一章、 導論 1
1-1 前言 1
1-2 研究動機 3
第二章、 低壓化學氣相沉積(LPCVD)之氮化矽薄膜 6
2-1 LPCVD之氮化矽薄膜製程介紹 6
2-2 不同成分比之氮化矽薄膜基本特性分析 7
2-2.1 薄膜之應力分析 7
2-2.2 薄膜之楊氏係數分析 11
第三章、 以高溫純氮退火降低氮化矽薄膜光學吸收之研究 13
3-1 高溫純氮退火之製程介紹 13
3-2 高溫純氮退火研究動機 13
3-3 不同溫度下高溫純氮退火之薄膜分析 15
3-3.1 厚度分析 15
3-3.2 鍵結密度 15
3-3.3 折射係數與能隙 19
3-3.4 光學吸收 19
3-4 不同時間下高溫純氮退火之薄膜分析 29
3-4.1 厚度分析 29
3-4.2 鍵結密度 30
3-4.3 折射係數與能隙 30
3-4.4 光學吸收 31
3-4.5 最佳退火參數的元素成分比例 33
第四章、 以低溫補氫退火降低氮化矽薄膜光學吸收之研究 36
4-1 低溫補氫退火之製程介紹 36
4-2 低溫補氫退火研究動機 36
4-3 SiN0.91H0.02不同溫度下低溫補氫退火之薄膜分析 37
4-3.1 厚度分析 37
4-3.2 鍵結密度 37
4-3.3 折射係數與能隙 38
4-3.4 光學吸收 38
4-4 SiN0.74不同溫度下低溫補氫退火之薄膜分析 39
4-4.1 厚度分析 40
4-4.2 鍵結密度 40
4-4.3 折射係數與能隙 40
4-4.4 光學吸收 41
第五章、 應用於LPCVD之單晶矽懸臂結構與製程流程設計 43
5-1 單晶矽懸臂結構 43
5-2 單晶矽懸臂製程設計 44
5-3 製程上遇到之困難與解決方案 52
5-3.1 光罩改良以增加蝕刻均勻度 52
5-3.2 改變基板厚度以降低蝕刻區域的厚度差 53
第六章、 總結與未來展望 55
6-1 總結 55
6-2 未來工作 56
6-2.1 應用於LPCVD之單晶矽懸臂低溫機械損耗 56
6-2.2 氮化矽薄膜低溫機械損耗 56
6-2.3 退火後之氮化矽薄膜低溫機械損耗 57
6-2.4 低溫機械損耗之扭力測試 58
參考文獻 60

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