- 學位論文
溶膠凝膠法製備氧化鉿與氧化鉭混合膜的特性探討
Characterization of HfO2 and Ta2O5 Mixed Film by Sol-Gel process
摘要
本論文使用溶膠凝膠法製備氧化鉿(HfO2)與氧化鉭(Ta2O5)及氧化鉿:氧化鉭((HfO2:Ta2O5)混合膜，研究溶膠凝膠過程中，水解縮合時間對成膜後在攝氏700度環境下退火，對薄膜特性之影響。 實驗中使用有機醇(Alcohol)及氯化物(Chloride:TaCl5,HfCl4)作為前驅物(precursor)，水作為反應物，經過醇解(Alcoholysis)，水解(hydrolysis)，縮合(condensation)後形成氧化物，以旋轉塗佈方式塗在矽基板及藍寶石基板，再以攝氏700度爐管退火持溫4小時，透過X-射線繞射分析(X-Ray Diffraction)，X射線光電子能譜儀(X-Ray photoelectron spectroscopy)及橢圓偏光儀(Spectroscopic Ellipsometer)等儀器的量測，對薄膜的晶體結構、化學鍵結、及光學特性探討。 XRD量測結果得知HfO2及Ta2O5皆為多晶結構(HfO2在不同的水解縮合條件下，皆有兩種結構同時存在，Ta2O5則為單一結構)，混合膜在攝氏700度退火，不同水解縮合時間，皆為單斜晶結構，在攝氏900度退火，有單斜晶系與四方晶系共存的結構。XPS量測後得知，使用溶膠凝膠法製備的薄膜，皆有機氧鍵殘留。但透過氧氣環境下的退火的混合薄膜，有機氧鍵的殘留較少。各薄膜的折射係數，由於結構有有機物殘留，或者氧化程度之差異，使折射係數有所差異。混合膜透過霍爾量測分析，得到比ITO玻璃更好的電性結果，確認製備出低數量級電阻的透明薄膜。
並列摘要
The aim of this research is to investigate the thin films properties of HfO2,Ta2O5 and the mixed film of HfO2:Ta2O5 by Sol-Gel process. In detail, the precursor of these studies is Alcohol and Chloride (TaCl5, HfCl4), the reactant is H2O. Firstly, the Oxide film could be formed after those following processes as Alcoholysis, Hydrolysis and Condensation. Secondly, the film could be coated on Silicon substrate and Sapphire by Spin Coating method. Thirdly, through thermal annealing in 700 degrees Celsius lasting 4 hours under N2 environment, Finally, the film’s crystal structure, chemical bonding and optical properties could be analyzed through some measuring equipments as X-Ray Diffraction(XRD), X-Ray photoelectron spectroscopy(XPS) and Spectroscopic Ellipsometer(SE). The structures of HfO2 and Ta2O5 by XRD are all polycrystalline (HfO2 with two kind of polycrystalline structures in different conditions of Hydrolysis condensation, Ta2O5with one kind of polycrystalline structure), and Mixed film presents only Monoclinic polycrystalline structure in different Hydrolysis condensation time and 700° C annealing cases. Monoclinic and Tetragonal structures coexist in 900 ° C annealing condition. From XPS results, all thin films of Sol-Gel process growth possess residual organooxygen bond. But there are fewer residual organooxygen bonds for the mixed film annealed in oxygen environment. Due to residual organooxygen bond and different oxidation condition, The refractive indices of the same kind films are different. The conductive properties of mixed films are better than ITO films by Hall effect measurement. To make sure the mixed film of HfO2:Ta2O5 can be a candidate material of TCO( Transparent Conductive Oxide) film with lower order ohm resistor.