鐵電薄膜鈦酸鋇之電性研究

Abstract

本論文之研究主題是週波磁控濺鍍法將鈦酸鋇薄膜沉積於白金、鎳酸鑭、釨酸鋇等三種底電極上，觀察其電性量測上的差異。由改變鍍膜溫度及鍍溫度及鍍膜氣氛（氧氣與氬氣分壓比）等不同製程條件設定研究長成薄膜之晶體結構、成分與電性上的變化，及三者之間的相互關係。鍍膜溫度由400℃變化到500℃，氬氣與氧氣分壓比Ar/O2由14/6至12/8變化，並對其進行材料物性及電性之特性分析。實驗數據顯示釨酸鋇底電極之多种特性比鎳酸鑭底電極更好，其最佳化條件為：鍍膜溫度500℃，氬氣與氧氣分壓比Ar/O2=12/8，薄膜厚度為4000A，薄膜具有介電常數達179，量測頻率100kHz，於外加電壓為1.5伏特時，薄膜的漏電流密度為2.4×10-6 A/cm2，鈦酸鋇薄膜之漏電流機制，主要為GBLC理論及蕭特基發射理論所造成；在外加電壓5伏特時，電滯曲線圖形之正負永久極化量差(+P)－(-P)為0.9uc/cm2，在經過700℃通氧退火後，極化量差為17.1uc/cm2，疲乏度量測在量測頻率200MHz，外加電壓2伏特時，可達10（10）次切換。700℃高溫熱處理後，介電常數明顯上升漏電流有便大趨勢，電滯曲線亦得到大幅改善，疲乏度會有提早疲乏效應。

A series of barium titanate (BaTiO3) thin films on Pt/SIo2/Si, BaRuO3/Si and LaNiO3/Si substrates were prepared by RF magnetron sputtering at var ous substrate temperature, Ar/O2 ratio. The range of deposition conditions are (1) 400℃ to 500℃ for substrate temperature, and (2) 30% to 40% for O2/(Ar+O2) ration. The crystallinility, dielectric properties, composition, P-E curve and fatigue of these films have been analyzed. Under optimized conditions, BaTiO3 thin films on BaRuO3/Si of thickness 4000A were obtained at 500℃, and O2/(Ar+O2) ratio 40% The film dielectric constant is 179 at 100kHz, and leakage current density of 2.4×10-6A/cm2 at 1.5V. The difference of the remnant polarization (△P) is 0.9uc/cm2 at 5V. After 700℃ annealing in O2, △P is 17.uc/cm2, Before annealing, this film doesn't discovered fatigue effect after 1010 cycles.