Study Of The Process And Dielectric Properties Of Nb₂O₅-TiO₂ And Nb₂O₅-Ta₂O₅ Ceramics

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.