鑽石膜的 TEM 分析

圖5-22 為 EELS mapping 結果，圖 5-23 為 EDS mapping 結果，由於 EELS 對於輕元素較靈敏，對重元素較不靈敏，EDS 則與之相反，因此我們使用 EELS 偵測 C、N、Si 元素，使用 EDS 偵測 C、Ti、Si 元素。從兩者 mapping 結果交互比對可知，最上層為碳，中間為TiN，基板為 Si， TiN 的 N 沒有 擴散到鑽石當中，為明顯的三層結構。

TiN 膜厚約為 250 nm，與前述 4.2.3 小節所得之 TiN 膜厚差異不大，鑽 石和TiN 的界面看起來十分平整，可見在電漿中 TiN 並沒有被蝕刻掉，達 到保護矽基板表面之目的。

圖 5-20 鑽石膜的 TEM 分析結果，(a)明視野影像，(b)SAD 影像。

圖5-21 (a)將特定鑽石晶粒調整至[011]區軸下之繞射圖。(b) 圖 5-19 (a)所得 之明視野影像，(c) 圈選圖 5-19 (a)中鑽石 200 繞射點所得之暗視影像。

圖5-22 EELS mapping。

圖5-23 EDS mapping，區域為長方形圈出之範圍。

5.4 結論

TiN 在氫電漿中，表面所覆蓋的 TiO₂能被氫電漿還原蝕刻，使TiN 露 出表面，造成顏色轉變為金黃色。經過氫電漿的反應後，TiN 的表面並沒有 太大的粗糙度改變，可保護矽基板表面不受損傷，有利於磊晶鑽石成長。

在相同成長條件下，在TiN 緩衝層上成長之鑽石可成膜，但在矽基板 上成長之鑽石仍未成膜，可知TiN 緩衝層的引用，有助於鑽石的成核密度 增加。

在不同磊晶程度的TiN 薄膜上成長鑽石，以 ImageJ 計算其方塊面積所 佔比例來比較<100>織構之鑽石膜品質，從計算結果可知當 TiN 磊晶程度較 佳時，<100>織構比例較高。從拉曼光譜分析來看，在品質較佳的 TiN 薄膜 上成長之鑽石sp²鍵結較少、鑽石品質較佳。然而，從傾斜之SEM 來看，

鑽石方塊並非以水平面朝上，且TEM 分析結果可知成長出(100)面之晶粒並 非從TiN 表面直接成長，而是從成核層表面長出，方向並非朝上。因此，

若欲得到(100)磊晶鑽石膜應從成核時間和成核條件改進。

第六章 結論

一TiN 結構，膜厚 265 nm，x-ray rocking curve (200)半高寬為 2.43˚，表 面粗糙度rms 為 3.10 nm，電阻率為 8.6 mΩ·cm。

(4) 從橫截面 TEM 可以得知不通入氮氣之製程所得之 TiN 為磊晶薄膜；而 以氮氣冷卻時，TiN 表面形成 15 nm TiO₂。

鑽石成長製程

(1) TiN 薄膜在氫電漿中，表面的 TiO₂層會被氫電漿還原，使顏色轉變成金 黃色，且表面粗糙度並不會改變很多。

(2) TiN 緩衝層的引用在相同成長條件和時間下，能成長出鑽石連續膜，根 據拉曼光譜分析結果可知TiN 緩衝層有助於改善鑽石品質。

(3) TiN 磊晶程度愈高，愈有利於<100>織構鑽石膜的成長。由拉曼光譜分析 可知鑽石品質與所使用之TiN 磊晶程度成正比。然而 SEM 中的方塊平 面並非水平朝上，鑽石(100)面不是垂直向上，且從 TEM 分析結果可知 (100)晶粒並非直接從 TiN 表面長出，而是從成核層表面向上成長。

(4) TiN 厚度在鑽石成長前後並無多大改變，且鑽石和 TiN 界面平整，表示 TiN 能不被電漿蝕刻、達到保護矽基板表面之目的。

(5) 以雷射頻率 10 Hz 製程 TiN/Si 為基板所成長之鑽石膜，以 ImageJ 計算

<100>織構比例最高為 54.7%。

未來建議與展望

首先，希望使TiN 表面更為平坦以利於鑽石磊晶成長。其次，調整成核時 間與成核條件使鑽石能以(100)面直接從 TiN 表面向上成長，並且使無缺陷 的(100)鑽石晶粒成長成較大的晶粒，相信對磊晶鑽石有更好的應用。 

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附錄一 ImageJ 使用方法

由美國國家衛生研究院(National Institutes of Health, NIH)所提供(http://

rsb.info.nih.gov/ij/)。以下為我們使用 ImageJ 來計算鑽石方塊面積比例的步 驟：

(1) 調整 SEM 影像中(100)晶粒之對比，在工具列上選 Process →Binary

→Make Binary，可得到一黑白對比影像。

(2) 在工具列上選 Analyze →Analyze Particles...，出現 Analyze Particles 視窗，

勾選Summarize，按下 OK 即開始計算。計算完畢後會跳出另一視窗，

即可知道(100)晶粒所佔的面積比例為何。

圖A ImageJ 使用流程圖

在文檔中 在具有氮化鈦緩衝層之(001)矽晶片上成長鑽石之研究 (頁 99-111)