The influence of the distribution of nano-pores on the mechanical properties evaluation of porous low-k films by surface acoustic waves （SAW） is studied. A theoretical SAW propagation model is set up to characterize...The influence of the distribution of nano-pores on the mechanical properties evaluation of porous low-k films by surface acoustic waves （SAW） is studied. A theoretical SAW propagation model is set up to characterize the periodic porous dielectrics by transversely isotropic symmetry. The theoretical deductions of SAW propagating in the low-k film/Si substrate layered structure are given in detail. The dispersive characteristics of SAW in differ- ent propagation directions and the effects of the Young＇s moduli E, E′ and shear modulus G′ of the films on these dispersive curves are found. Computational results show that E′ and G′ cannot be measured along the propagation direction that is perpendicular to the nano-pores＇ direction.展开更多
The effects of Li2O-MgO-B2O3 （LMB） glass additive on the sintering characteristics, phase purity, microstructure, and microwave dielectric properties of Li2MgTi3O8 ceramics were investigated. The experimental result...The effects of Li2O-MgO-B2O3 （LMB） glass additive on the sintering characteristics, phase purity, microstructure, and microwave dielectric properties of Li2MgTi3O8 ceramics were investigated. The experimental results demonstrate that the addition of LMB glass effectively lowers the sintering temperature of Li2MgTi3O8 ceramic from 1025 ℃ to 875 ℃ and induces no obvious degradation of the microwave dielectric properties. Typically, the 1.5%LMB glass-added Li2MgTi3O8 ceramic sintered at 875 ℃ for 4 h shows excellent microwave dielectric properties of Q×f=45403 GHz, εr=25.9 and τf≈0 ℃-1. The dielectric ceramic exhibits stability against the reaction with the Ag electrode, which indicates that the ceramics could be applied in multilayer microwave devices requiring low firing temperatures.展开更多
The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and mi...The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and microwave dielectric measurements. The experimental results show that a small amount of BaCu（B2O5） addition can effectively reduce the sintering temperature to 900℃, and induce only a limited degradation of the microwave dielectric properties. Typically, the best microwave dielectric properties of er24.5, Q×f =24 622 GHz, rf=4.2×10-6℃ -1 are obtained for 1.0% BCB-doped Li2MgTi3O8 ceramics sintered at 900℃ for 3 h. The BCB-doped Li2MgTi3O8 ceramics can be compatible with Ag electrode, which may be a strong candidate for low temperature co-fired ceramics applications.展开更多
文摘The influence of the distribution of nano-pores on the mechanical properties evaluation of porous low-k films by surface acoustic waves （SAW） is studied. A theoretical SAW propagation model is set up to characterize the periodic porous dielectrics by transversely isotropic symmetry. The theoretical deductions of SAW propagating in the low-k film/Si substrate layered structure are given in detail. The dispersive characteristics of SAW in differ- ent propagation directions and the effects of the Young＇s moduli E, E′ and shear modulus G′ of the films on these dispersive curves are found. Computational results show that E′ and G′ cannot be measured along the propagation direction that is perpendicular to the nano-pores＇ direction.
基金Project(2010GXNSFA013029)supported by National Undergraduates Innovating Experimentation Project of ChinaProject(101059529)supported by Natural Science Foundation of Guangxi,China
文摘The effects of Li2O-MgO-B2O3 （LMB） glass additive on the sintering characteristics, phase purity, microstructure, and microwave dielectric properties of Li2MgTi3O8 ceramics were investigated. The experimental results demonstrate that the addition of LMB glass effectively lowers the sintering temperature of Li2MgTi3O8 ceramic from 1025 ℃ to 875 ℃ and induces no obvious degradation of the microwave dielectric properties. Typically, the 1.5%LMB glass-added Li2MgTi3O8 ceramic sintered at 875 ℃ for 4 h shows excellent microwave dielectric properties of Q×f=45403 GHz, εr=25.9 and τf≈0 ℃-1. The dielectric ceramic exhibits stability against the reaction with the Ag electrode, which indicates that the ceramics could be applied in multilayer microwave devices requiring low firing temperatures.
基金Project(2010GXNSFA013029) supported by the Natural Science Foundation of Guangxi Province,ChinaProject(101059529) supported by National Undergraduate Innovation Program of the Ministry of Education of China
文摘The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and microwave dielectric measurements. The experimental results show that a small amount of BaCu（B2O5） addition can effectively reduce the sintering temperature to 900℃, and induce only a limited degradation of the microwave dielectric properties. Typically, the best microwave dielectric properties of er24.5, Q×f =24 622 GHz, rf=4.2×10-6℃ -1 are obtained for 1.0% BCB-doped Li2MgTi3O8 ceramics sintered at 900℃ for 3 h. The BCB-doped Li2MgTi3O8 ceramics can be compatible with Ag electrode, which may be a strong candidate for low temperature co-fired ceramics applications.
