空氣中燒結之鈦酸鍶變阻器電學性質的研究

Abstract

本論文之內容，在於研發鈦酸鍶型變阻器，並以各種不同電性量測，了解 其應用於實際環境的可行性，以及經由理論的分析，觀察鈦酸鍶型變阻器 之製程變因（燒結溫度）對元件的微結構與電氣特性的影響。此外，鈦酸 鍶型變阻器同時具有電容性與變阻器的優點，所以針對其製程和原理作深 入研究，以達多功能陶瓷為目標。於整個實驗中，我們將以一般氣氛燒結 的方式製備鈦酸鍶變阻器陶瓷，以取代傳統上以還原氣氛燒結，並且經過 二次熱處理的複雜製程，以達到製程簡單、成本低廉、物性良好之鈦酸鍶 變阻器，以符合工業生產的方式。同時對於不同製程參（燒結溫度）所製 造出來的變阻體元件，我們將進一步作電容－電壓分析及損耗因子的相關 探討。由於鈦酸鍶變阻體符合蕭特基能位障的模型。因此以電容－電壓分 析可經由理論推導出晶粒內載子濃度，晶界界面捕陷態密度和晶界的能位 障高度等物理量，利用這些物理量可以了解載子在變阻器元件內分佈和傳 導情形。 The influence of various sintering temperatures on the icrostructure and electrical properties of the air-fired SrTiO3 varistor was investigated. The average grain sizes of the speci- ens sintered at 1400?C , 1500?C, 1570?C for 4 hours are 14.5?15.1?m, 15.6?m,respectively. The nonohmic properties of the400?C sintered specimens are better than those of the 1500鱋nCnd 1570?C specimens. On the basis of theirI-V characteristics, t can be inferred that ?Bi2O3 phase existed in the grain boun- ary of 1400?C sintered samples would enhance the nonohmic char- cteristics of ceramic sintered samples would enhance the nonohmiccharacteristics of ceramic varistors. The increasing donor ration and the decreasing barrier height with increasing sinter-ng temperature were observed on the basis of C-Vanalysis. Thesamples sintered at 1400?C possess the highest grain boundary orphous by using A.C. conductivity data. The air-fired sample excellent nonohmic characteristics, but the dielectric proper-ies must be improved to develop mutifunctional device.