臺灣博碩士論文加值系統

本研究是利用溼式酸蝕刻法，藉由室溫下控制 HNW (hydrofluoric acid, nitric acid and water) 濕蝕液的成分比例與蝕刻時間、蝕刻面積，在多晶矽表面形成蝕刻織構 (texture)。
本研究是以場發射掃描電子顯微術 (field emission scanning electron microscopy, FESEM) 及原子力顯微術 (atomic force microscopy, AFM) 來分析經過蝕刻後的多晶矽表面結構與粗糙程度，也應用紫外-可見光分光光譜術 (ultraviolet-visible spectrometry, UV-VIS) 分析蝕刻前後多晶矽片在 400-800 nm 光譜範圍內的相對反射率，並採用薄膜測厚儀 (α-step) 測量蝕刻後的多晶矽的蝕刻深度及X光繞射術 (X-ray diffractometry, XRD) 分析各樣本的結晶面。
結果發現：利用 SEM 之觀察分析結果可以篩選出相對反射率值較低的矽晶片表面織構，而AFM 之分析可得知矽晶表面層經蝕刻後之粗糙度變化及其受二氧化氮氣泡影響的結果。採用HNW 配製比例為 4:1:2，且蝕刻時間15秒的蝕刻製程後的多晶矽片可獲致之最低相對反射率值為 43.16%。

Wet acid etchant was adopted to obtain etched texture on polycrystalline silicon wafers by controlling the composition of HNW (hydrofluoric acid, nitric acid and water) etchant, the etching period and the etching area at room temperature. The surface morphology and the roughness of etched area were analyzed by employing field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The etching depth was measured by using α-step. The texture variations were examined by applying X-ray diffractometry (XRD). Ultraviolet-visible (UV-VIS) spectroscopy was used to compare the relative reflectance of the blank and the etched specimens. The results showed that the relative reflectance of the etched specimens were correlated to their surface texture. It could be simply screened from SEM and XRD observations. AFM analyses indicated that the surface roughness at the near surface of silicon wafers affected by the impact of nitrogen dioxide. The optimal processing conditions to obtain the relatively lowest reflectance, 43.16%, in this study was: HNW ratio of 4:1:2 and etched at room temperature for 15 seconds.

目錄
誌謝1
摘要i
ABSTRACT ii
目錄v
表目錄vii
圖目錄viii
第壹章 序論1
1.1前言1
1.2研究動機2
1.3研究目的3
第貳章 基本理論4
2.1太陽能電池介紹4
2.2太陽電池光電轉換理論6
2.3矽晶的表面織構化原理9
第參章 實驗流程12
3.1製程架構12
3.2製程參數14
3.3實驗儀器16
第肆章 結果與討論21
4.1原材性質評估21
4.2 XRD數據分析多晶矽蝕刻前後的表面結構21
4.3 SEM與AFM的表面形貌分析與α-step蝕刻深度量測22
4.4 UV-VIS表面反射率分析25
第伍章 結論與建議27
5.1結論27
5.2未來展望28
參考文獻29
表目錄
表3- 1. 紫外-可見光分光光譜儀規格18
表4- 1. p型多晶矽原材粗糙度32
表4- 2. HNW (4:1:2) 蝕刻15秒的重量變化32
表4- 3. α-step測量多晶矽蝕刻深度與粗糙度 (Ra)33
表4- 4. HNW (4:1:2) 酸腐蝕多晶矽片15秒後粗糙度量測34
表4- 5. 多晶矽在可見光範圍內 (400-800nm) 的平均表面反射率量測35
圖目錄
圖2- 1. 太陽電池材料種類分類表 [12]4
圖2- 2. 矽的鑽石結構圖 [12]8
圖2- 3. 蝕刻反映機構10
圖3- 1.蝕刻實驗示意圖13
圖3- 2.實驗流程圖14
圖3- 3. (a) 及 (b) 蝕刻範圍為單一晶粒，(c)~(i) 蝕刻範圍為多晶粒的多晶矽樣本15
圖3- 4. 原子力顯微鏡圖16
圖3- 5. AFM原子顯微鏡運作示意圖17
圖3- 6. 薄膜測厚儀19
圖4- 1. p型多晶矽原材的SEM圖36
圖4- 2. p型多晶矽原材的AFM圖36
圖4- 3. p型多晶矽原材在可見光範圍內 (400~800 nm)範圍內的反射率曲線37
圖4- 4. 蝕刻前的X射線繞射光譜圖38
圖4- 5. 蝕刻後的X射線繞射光譜圖39
圖4- 6. 多晶矽蝕刻後的α-step群組長條圖40
圖4- 7. 蝕孔織構模型 [20]40
圖4- 8. (a)~(i).HNW (4:1:2) 酸腐蝕多晶矽片15秒的SEM圖43
圖4- 9. (a)~(i). HNW (4:1:2) 酸腐蝕多晶矽片15秒的AFM圖46
圖4- 10. HNW (4:1:2) 酸腐蝕多晶矽片15秒的AFM群組長條圖47
圖4- 11. HNW (4:1:2)，蝕刻 15秒的反射率曲線圖48
圖4- 12. HNW (4:1:2)，蝕刻 15秒的相對於多晶矽原材的反射率曲線圖49

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