【作者】 张秋林；

【导师】 王越；

【作者基本信息】 北京工业大学 ， 凝聚态物理， 2006， 硕士

【摘要】 随着电子科技的发展,微电子线路的集成化程度日益提高,这就要求集成元器件的尺寸越来越小,而对其性能的要求却越来越高。对电容元器件来说,介电性能限制了其集成化程度。随着计算机技术的快速发展,目前的电子材料已经不能够很好地满足微电子线路中电容元器件的性能要求。动态随机存取存储器(Dynamic Random Access Memory,简称DRAM)中的电容电介质层是用SiO2或Si3N4制成的,在常规测量条件(1MHz频率和25℃)下它们的相对介电系数εr分别为3.8和6.0,这已经远远不能满足当前越来越大的存储能力的需求。要研制生产1G以上存储能力的DRAM,寻找一种高介电系数和低介电损耗的新型材料已经成为当务之急。由于Nb2O5的制备与半导体工艺兼容,经过掺杂改性后相对介电系数能够达到100以上,因而Nb2O5成为DRAM的重要候选材料。研究Nb2O5掺杂改性的方法是先将掺杂的Nb2O5粉末制备成陶瓷,找出使其介电性能达到最优的掺杂比例和制备工艺,然后再把它研制成具有实际应用价值的电介质薄膜。本文采用传统固态反应的烧结方法研究了Nb2O5-TiO2和Nb2O5-Ta2O5体系介电陶瓷的制备工艺,分析了上述不同掺杂对Nb2O5基陶瓷介电性能的影响,并通过X射线衍射和电子扫描电镜等手段研究了各组分样品的晶体学形态和微观形貌,另外,本文还研究了各组分陶瓷的介电性能对频率和温度的依赖性,最后,本文还对Nb2O5-TiO2和Nb2O5-Ta2O5介电性能的各向异性进行了初步研究。本课题的研究,将对新型电介质存储材料的研究开发和应用提供实验依据,对下一代DRAM的研制具有指导意义,并将对社会的经济建设产生积极的作用。更多还原

【Abstract】 With the development of microelectronics, sizes of the microelectronic circuit become smaller and smaller. For capacitive components, dielectric constant of materials limits degree of miniaturization. For example, the capacitive dielectric layer of DRAM (Dynamic Random Access Memory) is now made of SiO2 or Si3N4. Their dielectric constants are 3.8 and 6.0 successively. It will not meet the need of memory capability in the near future. Materials with high dielectric constant and small loss values are urgent for next generation DRAM with over 1 G memory capability. Nb2O5 has been the preferred material for DRAM for its good compatibility with semiconductor technique and doped Nb2O5 has dielectric constant high than 100. To develop the practical dielectric layer, we should firstly study the preferred doping percent and sintering condition of doped Nb2O5 ceramic.Dielectric ceramic system of Nb2O5-TiO2 and Nb2O5-Ta2O5 has been prepared by conventional solid-state reaction technique. Variation of dielectric properties at 1MHz at 25°C as a function of composition in Nb2O5-TiO2 and Nb2O5-Ta2O5 polycrystalline pellets has been studied. The possible crystallographic phases were presented on the basis of analysis by X-ray diffraction. The microstructures were determined by means of scanning electron microscopy (SEM) observation on the surface of fracture. The dielectric constant and loss were measured to observe the relaxation behavior as a function of temperature and frequency. The mixed power was pressed by unilateral molding technology and the anisotropy behavior of dielectric property was measured. This research will impel the development and application of new dielectric storage material. It is some significance to the next generation DRAM development, and then it has the positive function to the social economic development.更多还原