添加錳對鈦酸鍶鋇薄膜的微觀結構與介電特性的影響

Abstract

本研究是利用溶膠-凝膠法在Pt / Ta / SiO2 /Si (100)的基板上製備(Ba0.7Sr0.3)(MnXTi1-X)O3 薄膜，x分別為0、0.02、0.04、0.06、0.08、0.1，並在550~800℃之間進行熱處理，以XRD鑑定其結晶相，以SEM、AFM觀察薄膜的微觀結構，並且利用半導體參數分析儀量測漏電流密度、電容值和計算出不同電場下的介電常數。所有薄膜均在650℃開始生成perovskite結構，(Ba0.7Sr0.3)O3薄膜在550~650℃之間存在BaXSr1-XTiO2CO3的中間相；而添加錳的薄膜，則在550~700℃之間存在中間相。由SEM與AFM觀察微觀結構顯示，錳有抑制晶粒成長且使整個結構緻密化的效果，乃由於錳的拖曳，使得晶界的移動率降低所致。經由電性量測的解果顯示，當x=0.1 mol%時，熱處理條件為700℃/1hr，可使漏電流密度在外加電壓為5V下，下降兩個order。

(Ba0.7Sr0.3)(MnXTi1-X)O3 [x＝0、0.02、0.04、0.06、0.08、0.1] thin films were deposited on Pt / Ta / SiO2 / Si(100) substrate by sol-gel and spin coating method and then annealed at temperature ranging from 550 to 800℃. The crystallization behavior and microstructural evolution of the films were investigated by XRD, SEM, and AFM. The leakage current density and dielectric characteristics were determined using semiconductor parameter analyzer. All thin films crystallized to perovskite at 650℃. The (Ba0.7Sr0.3)TiO3 films crystallized to an intermediate phase BaXSr1-XTiO2CO3 between 550~650℃；manganese addition to (Ba0.7Sr0.3)TiO3 , an intermediate phase is BaXSr1-XTiO2CO3 between 550~700℃. Manganese can controlling grain growth is attributed to decrease in grain boundary mobility due to solute drag. The specimen with a composition of x=0.1 films after annealing 700℃ for 1 hour, whose leakage current density is lower two orders than the ones with no adding manganese.