鉭鈮酸鍶鉍鐵電薄膜的性質

Abstract

在過去，鉭鈮酸鍶鉍鐵電薄膜的研究多著重在如何用各種沈積方式，成長出鐵電性質較佳的薄膜。其中大多數的實驗，底電極都是應用鉑，並且討論薄膜沈積完成後的退火條件對鐵電性質的改善。但是因為過高的晶化溫度，使得鉭鈮酸鍶鉍鐵電薄膜和矽製程的集成有一定程度的困難。再加上鉑蝕刻後的產物揮發性低，不易於製作圖樣、和二氧化矽的附著性差及會與鉭鈮酸鍶鉍鐵電薄膜中的鉍形成化合物而破壞鐵電性…等。故本實驗利用固溶體的特性來降低製程溫度，並去除退火過程而將實驗變因著眼於基板溫度及氧偏壓來簡化製程。此外，用銥取代鉑來克服上述的缺點。本文探討鉭鈮酸鍶鉍薄膜於不同基板溫度及氧偏壓下沈積在金屬銥上的各種鐵電性質。

This work investigated how substrate temperature and O2/(Ar+O2) mixing ratio (OMR) affects the ferroelectric properties of thin films of Sr0.8BixTa1.2Nb0.8O9±y (x=2.44-2.6) (SBTN) on Ir/SiO2/Si substrate prepared by rf-magnetron sputtering. According to this study, SBTN film deposited at substrate temperature of 510oC and OMR of 20% has best ferroelectric properties. The remanent polarization (2Pr) of 40.218 mC/cm2 and coercive electric field (2Ec) of 70.82 kV/cm in this SBTN film. It also has highest dielectric constant (k = 390) in all conditions. However, high leakage current may damage its properties in practical use. With the measurement, we found the leakage current causes by defects in the SBTN films. The fatigue test shows no fatigue for all films up to 1010 switching cycles.