bst组分梯度铁电薄膜的性能分析word格式论文.docxVIP

优秀毕业论文 精品参考文献资料 摘 要 钛酸锶钡（Ba1-xSrxTiO3，BST）薄膜是钛酸钡、钛酸锶的固溶体，它具有介电常 数大、介电损耗低、调谐率高以及温度稳定性能好等特点，因而在介质移相器、压控 振荡器等领域有广泛的应用前景。组分梯度结构 BST 薄膜可拓宽材料的温度稳定区 间，从而改善薄膜的温度稳定性能；可缓和材料内部的应力及界面效应等，继而提高 薄膜的介电性能，成为目前国内外的研究热点。 本文研究了磁控溅射法制备 BST 铁电薄膜的工艺技术，沉积了上组分梯度结构、 下组分梯度结构和单层结构共三类 BST 薄膜，分析了这些薄膜的介电性能、温度稳定 性能和微结构性能以及不同缓冲层对薄膜介电性能的影响，并证实了薄膜内部组分梯 度结构的存在。 实验结果表明：随着溅射时间的延长（90min-150min），薄膜的优值因子从 47.3 降至 3.5；随着退火温度的升高（550℃-650℃），薄膜的优值因子从 56.3 降至 37.5； 而在 20%-40%的溅射氧分压条件下，氧分压为 30%时薄膜的优值因子达到最高值 54.7。相比于单层结构和上组分梯度结构，下组分梯度结构 BST 薄膜具有最小的介温 变化率 7.8%、最高的优值因子 66.2 和最低的表面粗糙度 1.418nm；组分梯度结构有 效的解决了 BST 薄膜的温度稳定性问题，改善了薄膜的介电性能。此外，缓冲层的引 入有利于促进材料的生长结晶，缓和薄膜与基片之间的晶格失配，从而改善薄膜的介 电性能；溅射有同质缓冲层的 BST 薄膜具有最好的结晶性能和最高的优值因子 53.3。 关键词：磁控溅射；组分梯度；温度稳定性能；EDS 线扫描；优值因子 II Abstract Ba1-xSrxTiO3 (BST) thin film is the solid solution of barium titanate and strontium titanate, has a wide range of applications in the medium phase detector, voltage controlled oscillators and other areas for its large dielectric constant, low dielectric loss, high tunability and good temperature stability. Compositionally graded BST thin films can improve the temperature stability by broadening the temperature stable range of materials and enhance the dielectric properties by easing the internal stress and interface effects between films. In this paper, the magnetron sputtering technology is studied. Upgraded, downgraded and single-layer structure BST thin films are deposited on Al2O3 substrates to investigate the dielectric properties, temperature stability and microstructure properties. Besides, the functions of buffer layers are researched and the internal components gradient is verified. The results show that: With the extension of sputtering time (90min-150min), the FOM of films decrease from 47.3 to 3.5; As the increase in annealing temperature (550℃ -650℃), the FOM of films dropped from 56.3 to 37.5; In the sputtering oxygen partial pressure of 20%-40%, the fabricated films with 30% oxygen partial pressure shows the highest FOM of 54.7. Compared