應用銅銦鎵三元合金靶材於銅銦鎵硒薄膜之研究

Utilization of CuInGa Ternary Alloy Target on CIGS Thin Films

何偉豪(Wei-Hao Ho)

指導教授 ： 蘇程裕

國立臺北科技大學/機電學院/製造科技研究所/碩士(2011年)

摘要

現今的銅銦鎵硒（Cu(In1-xGax)Se2, CIGS）薄膜技術多採用兩階段製程（Two-Step Process），於第一階段合成前驅層薄膜時，為求成份均勻，常須使用多道製程沉積多層結構薄膜，甚至多靶共濺鍍製程，如此程序較為繁瑣。此外，CIGS薄膜屬於多元化合物半導體，薄膜的化學組成與結構缺陷直接影響材料光電性質，生產過程所需控制的製程參數較多，技術門檻較高，故製程穩定性尚且不足。因此，發展一套製程穩定、簡易的CIGS薄膜技術有其必要性。
本研究著重於濺鍍/硒化製程研究，將前驅層中Cu、In、Ga 三種金屬元素製備成單一合金靶材，直接濺鍍即可獲得成份均勻的CuInGa前驅層薄膜，並配合硒化反應合成CIGS薄膜，同時討論前驅層薄膜製備條件，以及硒化製程參數對CIGS薄膜之成份、微結構以及光電性質之影響。
研究結果顯示，Mo薄膜內應力與附著性，隨著工作距離減小而急遽上升；調控工作壓力與濺鍍功率則可改善薄膜結晶性與導電性。最佳濺鍍條件為工作距離5.5cm、濺鍍功率72W、工作壓力5×10-3Torr，Mo薄膜的片電阻值為0.25Ω/□，同時具備良好附著性，符合太陽電池電極層要求。使用CuInGa三元靶材製備前驅層薄膜，薄膜主要結構為Cu11(In,Ga)9，濺鍍功率密度為0.2W/cm2時，可得平坦且緻密表面形貌，如此可說明應用CuInGa三元靶材於CIGS薄膜製程具有可行性。四階段硒化製程改善二階段硒化製程中成份損失問題，CIGS薄膜的Cu/(In+Ga)比例分別為0.85、0.96及1.01，薄膜呈現In-rich組成，並為單一黃銅礦相結構，具有(112)擇優取向，載子濃度約為1.566×1019-1.66×1020cm-3。

關鍵字

銅銦鎵硒太陽電池 ； 硒化製程 ； 銅銦鎵三元靶材

並列摘要

In this study, CIGS films were fabricated by selenization of single-sputtered CuInGa precursors using a CuInGa ternary alloy target. The effects of 2-stage and 4-stage selenization process on the CIGS thin films were investigated. SEM, XRD, EPMA and Hall meansurement were used to indentify the morphologies, micro-structures, compositions and electrical properties of the CIGS thin films. It was found that CuInGa precursors show Cu11(In,Ga)9 single phase with Cu/(In+Ga) ratio between 0.80-0.85, corresponding to the stoichiometric proportion of CuInGa target. As the sputtering power is maintained at 0.2 W/cm2, the CuInGa precursor shows flat topography with small grain size of 80–100 nm. All selenized CIGS films exhibited chalcopyrite structure with preferred orientation along (112) plane and In-rich componet with Cu/(In+Ga) between 0.85-1.01. Material loss in 2-stage selenization process was reduced by inducing 4-stage selenization procedure. The surface roughness of CIGS films depended on the topography of the precursors which could be improved by reducing the sputtering power density. Hall measurement on CIGS films yielded carrier concentration of -1.566×1019-1.66×1020 cm-3. In conclusion, utilizing CuInGa ternary target on precursor deposition is a possible way for CIGS thin film preparation which beneficially simplifies the manufacturing procedures and precisely controls the composition.

並列關鍵字

CIGS solae cells ； Selenization process ； CuInGa ternary target

參考文獻

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