添加鋯對鈦酸鍶鋇薄膜的微結構與介電特性的影響

Abstract

本研究嘗試以溶膠-凝膠方法在Pt/Ta/SiO2/Si(100)基板上製備(Ba0.7Sr0.3)(ZrxTi1-x)O3薄膜，並在400℃~850℃之間進行熱處理，以XRD鑑定結晶相，以SEM、TEM觀察薄膜的微觀結構，並量測漏電流密度、介電數值和計算單位體積可儲存之電容。鋯的含量x = 0、0.05、0.1、0.15、0.2，當x = 0時，(Ba0.7Sr0.3)TiO3的成相溫度在550℃左右開始形成，並在500℃ ~ 650℃之間鑑別出結晶的 (Ba,Sr)CO3中間過渡相；添加高熔點的鋯元素之後，(Ba0.7Sr0.3)(ZrxTi1-x)O3的成相溫度約在650℃左右，500℃ ~ 700℃鑑別出(Ba,Sr)O2的中間過渡相。由SEM微結構觀察得之， Zr有抑制晶粒成長的效果，此亦為介電常數會增加的原因。經由電性量測的結果得知，當x = 0.1時，熱處理溫度為800℃二小時，可得最佳電性，介電常數為450，漏電流密度為10－８A/cm2。

(Ba0.7Sr0.3)(ZrxTi1-x)O3 [x = 0、0.05、0.1、0.15、0.2] thin films were deposited on Pt/Ta/SiO2/Si(100) substrate by Sol-Gel and spin coating methods and then annealed at temperature ranging from 400℃ to 850℃ . The crystallization behavior and micro structural evolution of the films were investigated by XRD, SEM, and TEM . All thin films crystallized to perovskite at 550℃. The (Ba0.7Sr0.3)TiO3 films crystallized to an intermediate phase (Ba,Sr)CO3 between 500℃~ 600℃ and crystallized to cubic (Ba0.7Sr0.3)TiO3 phase above 650℃. Zicronia addition to (Ba0.7Sr0.3)TiO3 , an intermediate phase is (Ba,Sr)O between 500℃~ 700℃. Zicronia can controlling grain growth is attributed to a decrease in grain boundary mobility due to solute drag. The Specimen with a composition of x = 0.1 had optimum electric properties. A dielectric constant of 459 and leakage current density of 10-8 A/cm2 were measured for the (Ba0.7Sr0.3)TiO3 films after annealing at 800℃ for 2hours.