| Recent years, electrical integration and optical integration technology with small size and large capacity are developing in a high speed with the development of network, electrical, optical, communications and other technology. Microwave dielectric is wildly used in modern communication technology and promotes the development of device integration, miniaturization. However, the dielectric materials with excellent properties need a high annealing temperature which will increase the film surface roughness and damage the capacitors’ properties. The high temperature makes it incompatible with the standard metallization process. Therefore, the research of low-temperature materials with good dielectric properties has great significance.This paper’s aim is to solve the problem of the high annealing temperature after thin film deposition. In this paper, one kind of microwave ceramics with excellent microwave properties and a super low sintering temperature was selected to prepare the sputtering ceramic target and make the MIM capacitor. Thus, the film could be co-fired with gold electrodes at low annealing temperature. After researching of ZTT thin film capacitors’ dielectric properties, we had the main results as follows:1. The Zn2Te3O8-30wt%Ti Te3O8 tellurium-based microwave ceramic was prepared by solid state reaction, and the performance of the ZTT microwave ceramic was tested in the cavity resonance method. The results showed that: the ZTT ceramic has a resonant frequency of 8.5GHz which in the size of 12mm(D)×6mm(H), a relative dielectric permittivity(k) of 25.5, a Q×f-value of 56191 GHz, a loss of 1.51×10-4 and a temperature coefficient of resonant frequency(τf) of 1.66×10-6/℃. It’s sintering temperature is as low as 600 ℃. According to the conclusions, we prepared a 141mm-diameter, compact surface without cracks sputtering ceramic target to suit the equipment of the radio frequency magnetron sputtering.2. The ZTT dielectric thin film was prepared by RF magnetron sputtering on alumina substrate which is glazed in advance by ourselves. The effect of thin film preparation process parameters to thin films’ micro-structure and dielectric properties was studied to get the optimized ZTT film preparation technology. And the optimum condition is as follows: sputtering power 200 W, barometric pressure 0.34 Pa, substrate temperature 200℃, oxygen-argon ratio 1:2.3. We also studied the different micro-structure and dielectric properties of ZTT film before or after annealing. The results showed that: ZTT film could not crystal after annealed, there was no big improve on the dielectric constant, but the loss of ZTT thin film would decrease. while the annealing temperature is 380℃, the loss of the capacitor was declined from 1.6% to 0.7%, and the quality factor was increased. In this way, the film capacitor’s dielectric properties can be improved.4. The film capacitor in MIM structure was prepared under the optimum condition and a series of electrical properties were studied. The results showed that the film capacitor has a dielectric constant of 19.6, a quite low loss of less than 0.5%, a capacitance density of 0.35fF/μm2, and a voltage linearity of 7.5ppm/V2 and a leakage current density of less than 50×10-8A/cm2, the breakdown voltage is greater than 100 V. Such MIM capacitance has a perfect voltage stability and good frequency stability, and it also could anneal with gold electrode. According to such results, the MIM capacitor has good properties which basically satisfied the market requirements. |
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