製程參數對於溶膠凝膠法沉積鐵酸鉍薄膜之影響研究

Effect of Process Parameters on Bismuth Ferrite Thin Films by Sol-Gel Method

鐵酸鉍是一種無鉛多鐵性鈣鈦礦材料，本研究的目標為探討不同製程參數對使用溶膠凝膠法所製備鐵酸鉍薄膜之表面形貌與相組成的影響。研究中改變的製程參數有薄膜層數、退火時間、退火環境、基板選擇，以及旋轉塗佈轉速。當選擇銅片做為基板沉積薄膜並在真空環境下退火時，薄膜中會存在大量氧化鉍二次相。而當薄膜的退火過程選擇在大氣下進行，則發現樣品中存在大量氧化銅。選擇以鋁片做為基板沉積薄膜並在大氣環境下退火，改變旋轉塗佈轉速發現，經轉速4000rpm塗佈的薄膜表面形貌最為平整且緻密，經過XRD繞射分析後發現薄膜相組成以鐵酸鉍相為主。當薄膜的退火過程選擇在真空環境下進行，則發現樣品的薄膜表面存在大量孔洞。

 

Bismuth ferrite is a lead-free multiferroic perovskite material. The objective of this study is to investigate the influence of process parameters on the surface morphology and phase composition of bismuth ferrite thin films deposited by the sol-gel method. Various process parameters were considered, including the number of film layers, the annealing time, the substrates, and the rotational speed of the spin coating machine. While copper substrates were used for thin film deposition with a vacuum annealing, a large amount of bismuth oxide phase was found in the films. In contrast, when the annealing process of the films was conducted under an ambient atmosphere, a large amount of copper oxide was detected in the thin films. For aluminum substrates with an ambient atmosphere annealing, the primary phase composition was bismuth ferrite in the X-ray diffraction (XRD) analysis of the thin films. While the rotation speed of the spin coater was increased to 4000 rpm, the films exhibited the optimal properties with smooth and dense surface morphologies. However, a significant number of pores was found on the surface of the thin films while the annealing process was performed in a vacuum environment.