第四章 結果與討論
4.4 薄膜光學性質分析
表4-5 薄膜光穿透率與信號雜訊比(S/N)
S/N ratios of transmittance (dB)
Note:A=Power(W), B=pressure(mTorr), C=Temperature (℃), D= Time(min)
4.5 灰關聯分析與驗證實驗 灰關聯分析與驗證實驗 灰關聯分析與驗證實驗 灰關聯分析與驗證實驗
數組合，如表4-10所示。
表4-9 灰關聯因子之變異數分析
S/N ratios of grey relation
120
Note:A=Power(W), B=pressure(mTorr), C=Temperature (℃), D= Time(min)
表4-10 本系統最佳參數組合
沉積時間不若直交表序列來的長，粒子還處於孕核狀態時就停止鍍膜，使 粒子沒有足夠時間來聚結形成更大的結晶，故表面形態為較平整的片狀連 續膜(厚度約為170 nm)，由灰關聯預測所得之參數組合所鍍製的薄膜，因 有較長時間可讓粒子於基板表面進行擴散、互相結合，其表面形態為較粗 糙且凹凸不平的島狀連續膜(厚度約為1 µm) [54] ，也因表面較為粗糙，所 以薄膜透光率稍稍下降；在電阻率方面，由於片電阻值相較於直交表序列 所鍍製的薄膜大幅下降(直交表:1573 Ohm/sq 優於灰關聯186 Ohm/sq)，即 使薄膜厚度較厚，但本文電阻率是由(3-5)式所求得，經過計算，由灰關聯 所鍍製之薄膜電阻率還是比直交表所鍍製之薄膜來的好。
圖4-10為薄膜之XRD繞射圖，由灰關聯所預測參數組合所鍍製的薄膜 雖然繞射強度與直交表序列參數組合相較之下並不明顯， 但其半高寬(b:
full-width at half-maximum, FWHM)仍比直交表序組合低，顯示其晶粒尺 寸較大，由此可知，由灰關聯所預測之參數組合為本系統最佳沉積參數。
(a) 50 W, 7.5 mTorr, 50 ℃, 40 min (b) 50 W, 7.5 mTorr, 50 ℃, 60 min 圖4-7 AFM薄膜表面形態
(a) 直交表序列參數組合所鍍製之薄膜 ( Ra : 0.305 nm ) (b) 灰關聯預測參數組合所鍍製之薄膜 ( Ra : 0.529 nm )
(a) 50 W, 7.5 mTorr, 50 ℃, 40 min (b) 50 W, 7.5 mTorr, 50 ℃, 60 min 圖4-8 SEM薄膜表面形態
(a) 直交表序列參數組合所鍍製之薄膜 ( Thickness :約170 nm ) (b) 灰關聯預測參數組合所鍍製之薄膜 ( Thickness :約300 nm )
圖4-9 薄膜光穿透率圖
(a) 直交表序列參數組合所鍍製之薄膜(Transmittance : 87.6 %) (b) 灰關聯預測參數組合所鍍製之薄膜(Transmittance : 83.0 %)
圖4-10 薄膜XRD繞射圖 (b為半高寬)
(a) 直交表序列參數組合所鍍製之薄膜 (b) 灰關聯預測參數組合所鍍製之薄膜
4.6 改變 改變 改變 改變射頻功率 射頻功率 射頻功率 射頻功率
經實驗驗證後，得知灰關聯預測因子(50 W, 7.5 mTorr, 50 ℃, 60 min) 為本系統最佳沉積參數組合，再將此組合選出最重要參數因子功率並改變 其鍍膜參數，如表4-12所示，觀察對GZO透明導電膜之表面結構、XRD繞 射強度、電阻率及光穿透率的影響。
表4-12 改變功率鍍膜參數表
Substrate PET 25mm × 25mm × 0.1mm
Target
ZnO: Ga2O3 (97:3 wt . %)；
99.9 95 % p uri t y; 51. 2 mm diameter
Gas Argon (99.995%)
Base pressure 5.0 × 10-6 torr Substrate-to-target distance 85 mm
Substrate rotate vertical axis 30 rpm Sputtering pressure 7.5 mTorr
Temperature 50℃
Deposition time 60 min
R.F. power 30, 40, 50, 60,70 W
4.6.1 薄膜表面結構分析 薄膜表面結構分析 薄膜表面結構分析 薄膜表面結構分析
圖4-11(a)~(e)為改變功率鍍膜參數下的氧化鋅鎵薄膜表面形態，可看 出當射頻功率增大時，可發現薄膜表層結晶有明顯變大的趨勢。
(a) RF power 30 W (b) RF power 40 W
(c) RF power 50 W
(d) RF power 60 W (e) RF power 70 W
圖4-11 改變功率鍍膜參數薄膜表面結構(a)~(e)
4.6.2 薄膜 薄膜 薄膜XRD繞射分析 薄膜 繞射分析 繞射分析 繞射分析
圖4-12為改變功率鍍膜參數下薄膜XRD繞射圖，可明顯得知隨著射頻 功率的提升，其薄膜的繞射峰強度越強。在射頻功率為30 W時其強度已無
法測知，可能是因為射頻功率過低，使得粒子無法有效的附著在基材上。
利用繞射峰的半高寬(Full width half maximum, FWHM)可以計算出晶 粒大小D，其關係式如下[55]：
D = cos
k b
λ
θ (4-1) 其中 k=0.9 為常數，λ為 X-ray入射波長(λ=1.54Å)，b為半高寬(弳 度)，θ為繞射角度，由上式可知當半高寬變小時，其結晶顆粒會越大。
圖4-12 改變功率鍍膜參數薄膜XRD繞射圖 (b為半高寬)
4.6.3 薄膜電性分析 薄膜電性分析 薄膜電性分析 薄膜電性分析
圖4-13為改變功率鍍膜參數下薄膜電阻率圖，隨著射頻功率提升，薄 膜電阻率有明顯下降的趨勢，在功率為30 W~50 W時，電阻率急速下降，
而在50 W~70 W時電阻率下降的速度趨於平緩。
圖4-13 改變功率鍍膜參數薄膜電阻率圖
4.6.4 薄膜光穿透率分析 薄膜光穿透率分析 薄膜光穿透率分析 薄膜光穿透率分析
圖4-14為改變功率鍍膜參數下薄膜光穿透率圖，可得知隨著射頻功率 的改變，薄膜的可見光穿透率隨之成正比的趨勢。
圖4-14 改變功率鍍膜參數薄膜光穿透率圖
4.7 改變 改變 改變 改變濺鍍 濺鍍 濺鍍 濺鍍壓力 壓力 壓力 壓力
經實驗驗證後，得知灰關聯預測因子(50 W, 7.5 mTorr, 50 ℃, 60 min) 為本系統最佳沉積參數組合，再將此組合選出次重要參數因子壓力並改變 其鍍膜參數，如表4-13所示，觀察對GZO透明導電膜之表面結構、XRD繞 射強度、電阻率及光穿透率的影響。
表4-13 改變壓力鍍膜參數表
Substrate PET
Target
ZnO: Ga2O3 (97:3 wt . %)；
99.9 95 % p uri t y; 51. 2 mm diameter
Gas Argon (99.995%)
Base pressure 5.0 × 10-6 torr Substrate-to-target distance 85 mm
Substrate rotate vertical axis 30 rpm
R.F. power (W) 50 W
Temperature 50℃
Deposition time 60 min
Sputtering pressure 6.75, 7.13, 7.5, 7.88, 8.25 mTorr
4.7.1 薄膜表面結構分析 薄膜表面結構分析 薄膜表面結構分析 薄膜表面結構分析
圖4-15(a)~(e)為改變壓力鍍膜參數下的氧化鋅鎵薄膜表面形態，可看 出當製程壓力改變時，發現薄膜表層結晶有並無明顯變化。
(a) Pressure 6.75 mTorr (b) Pressure 7.13 mTorr
(c) Pressure 7.5 mTorr
(d) Pressure 7.88 mTorr (e) Pressure 8.25 mTorr 圖4-15 改變壓力鍍膜參數薄膜表面結構(a)~(e)
4.7.2 薄膜 薄膜 薄膜XRD繞射分析 薄膜 繞射分析 繞射分析 繞射分析
圖4-16為改變壓力鍍膜參數下薄膜XRD繞射圖，可明顯得知當改變濺 鍍壓力的情況之下，得知通以適量的氬氣，對於晶粒的強度提升，有相當 大的幫助。
圖4-16 改變壓力鍍膜參數薄膜XRD繞射圖 (b為半高寬)
4.7.3 薄膜電性分析 薄膜電性分析 薄膜電性分析 薄膜電性分析
圖4-17為改變壓力鍍膜參數下薄膜電阻率圖，隨著濺鍍壓力的提升，
電阻率有上升的趨勢，當壓力處於7.5mTorr的情況下，薄膜的電阻率達到 最高。
圖4-17 改變壓力鍍膜參數薄膜電阻率圖
4.7.4 薄膜光穿透率分析 薄膜光穿透率分析 薄膜光穿透率分析 薄膜光穿透率分析
圖4-18為改變壓力鍍膜參數下薄膜光穿透率圖，可得知當濺鍍壓力在 7.5mTorr時，光穿透率能夠達到最佳的狀態，不論是改變瓦數或是改變壓 力的情況下其最佳光穿透率在可見光(500~600 nm)範圍，都有80 %以上之 光穿透率。
圖4-18 改變壓力鍍膜參數薄膜光穿透率圖
第五章 第五章
第五章 第五章 結論 結論 結論 結論
本研究以RF磁控濺鍍沉積氧化鋅鎵(GZO)薄膜於PET 上，以田口實驗 設計配合灰關聯分析，探討製程參數及再線性對GZO薄膜光電性質的影 響，茲將本文結論歸納如下：
1. 經由田口實驗之變異數分析後可得知，射頻功率為影響薄膜沉積速率 及電阻率的主要因子；隨著射頻功率的提升，靶材上被濺射出的粒子 有更大的動能向基板移動，當粒子到達基板表面時，也有足夠的能量 進行擴散使其再結合，形成較大的晶粒，電子只需通過較少的阻礙來 進行傳遞。此外，影響薄膜透光率的主要因子為濺鍍壓力，當濺鍍壓 力在7.5 mTorr時，光穿透率能夠達到最佳的狀態。
2. 由灰關聯理論分析，經實驗應証，求得本系統多重品質特性最佳鍍膜 參數，其水準組合為 : 射頻功率 50 W、濺鍍壓力 7.5 mTorr、濺鍍溫 度 50 ℃、沉積時間 60 min，所獲得的沉積速率為5.12 nm/min、電阻 率為5.5×10-3 Ω‧cm、表面粗糙度為0.529 nm及可見光穿透率約為83
%。
3. 在改變單一鍍膜參數下，不論是改變瓦數或是改變壓力，其電阻率及 光穿透率，皆比灰關聯鍍膜參數組合要來的差，故再次驗證灰關聯鍍 膜參數組合是本次實驗參數設置中之最佳鍍膜參數。
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