低温烧结SrTiO3陶瓷晶界层电容器材料的掺杂分析

借助于晶格常数的精确测定、透射电子显微镜及其电子衍射和X射线能谱分析,结合材料性能,对还原气氛中低温一次烧结的srTiO_2陶瓷晶界层电容器材料的掺杂状况进行了分析。结果表明Li~+不能进入srTiO_2晶格的填隙位置形成施主。在Nb_2O_5和Li_2O同时存在的情况下,也没有产生施主-受主相互补偿进入晶格的现象,而是Nb_2O_5进入晶格起施主作用使晶粒半导化,Ll_2O偏析在晶界上,与聚集在晶界上的SZO_2一起形成活性液相,促进烧结的进行,并形成复杂的锂硅酸盐化合物产生绝缘性的晶界,从而形成晶界层电容器的显微结构,这是能够在低温下一次烧成SrTiO_2陶瓷晶界层电容器材料的根本原因。

THE DOPING ANALYSIS OF SrTiO_3 GBBL CAPACITORS SINTERED AT LOW TEMPERATURES

By use of cell parameters measurement, transmission electron microscopy, electron diffraction and X-ray energy spectrum, and combining with the properties of the samples, the doping state of SrTiO, GBBL capacitors single-fired at low temperature in reducing atmosphere was analyzed. The results show that Li~+ ion can not incorporate into the interstitial site of SrTiO_3 lattice to act as a donor. Under the circumstance of coexistance ofNb_2O_5 and Li_2O, the phenomenon of incorporation into lattice by donor-acceptor compensation mechanism does not occur. The microstructure of SrTiO_3 GBBL capacitors is developed by the incorporation of Nb_2O_3 into SrTiO_3 lattice, which makes grain semiconducting, and the precipitation of Li_2O in grain boundaries, which makes grain boundaries insulating by forming comphcated lithium silicates and promotes sintering process by forming reactive liquid phase with SiO_2 assembled in grain boundaries. That is the essential reason why SrTiO_3 GBBL capacitors can be single-fired at low temperatures.