JPS5935481B2 - oxide dielectric materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxide dielectric material containing Ca, Zn, Pb, and Nb as main components.

The purpose of the present invention is to provide a microwave dielectric material having a dielectric constant (ε) of 17 or more, a small dielectric loss (tan δ), and a temperature coefficient of dielectric constant (εT) that can be controlled to any positive or negative value. An object of the present invention is to provide an oxide dielectric material suitable for materials and capacitor materials. Dielectric materials have been widely applied to impedance matching in microwave circuits, dielectric resonators, and the like.

This trend has been further accelerated, and in recent years, with the increase in communication networks, the frequency range used has expanded to the low frequency range, quasi-millimeter wave range, and millimeter wave range, and with the demand for microwave ICs, peripheral technologies have advanced. In conjunction with this, it is possible to stabilize the oscillator frequency, control the delay time, and improve microwave circuit engineering.
Active consideration is being given to using dielectric materials with high dielectric constant and low loss for substrates and the like. BaO-jTi02-based materials are known as conventional general dielectric materials, but the dielectric constant temperature coefficient εT exhibits a large negative value and a positive value cannot be obtained.

In addition, alumina sintered body, MgTiO3 system, CaTi03
In systems, positive values can be obtained while other conditions are satisfied, but if you try to obtain values ranging from positive to negative, δ becomes large. The present invention eliminates these drawbacks, and by constructing an oxide dielectric with a four-component system of CaO-ZnO-PbO-Nb2O5, the temperature coefficient of permittivity can be changed over a wide range from positive to negative. To provide an excellent dielectric material with high dielectric constant and low loss that exhibits excellent characteristics for micro devices, capacitor devices, temperature compensation devices, etc. that can be controlled arbitrarily. Furthermore, CaO-ZnO-PbO-N according to the present invention
In an oxide dielectric material consisting of a four-component system of b2O5,
(CaO)a(ZnO)b(PbO)c(Nb2O5)
When hail d occurs, the composition ratios of each component system are a, b, c,
d(7) The total sum is 1, and each composition ratio is 0.050≦
a≦0.450, 0.10≦≦0.60, 0.0≦c
≦0.035 and the remaining d satisfies the conditions, and exhibits particularly excellent characteristics.

Hereinafter, the present invention will be explained in detail by giving an example of implementation. Data for individual examples include CaO, ZnO, Pb
The raw materials for O and Nb2O5 are weighed according to their respective compositions, mixed in a ball mill, filtered and dried, then calcined for 4 hours at a temperature of 1000°C, and after compression molded at a temperature of 1160 to 1250°C.
This was measured using a sample obtained by firing at a temperature of 2 hours in the air or oxygen atmosphere.

The dielectric constant was measured at room temperature, the temperature coefficient of the dielectric constant, etc. were measured in the microwave band from IMHz to the X band. The composition of the oxide dielectric material in which the present invention is implemented is (CaO)a(ZnO
) b (PbO) c (Nb2O5) d, when a
+b+c+d=1.00 while each A
, b, c, and d, various characteristics measured at the X-band frequency (6 GHz) are shown in Table 1.

As shown in Table 1, CaO/ZnO/PbO/Nb2O
5, the temperature coefficient of dielectric constant εT. K becomes smaller and +35 between compositions of C=0.0164 and 0.0323.
It shows a small change from P/℃ to -101P/℃.

Especially a=0.129, b=0.5161, c=0.03
23, the composition of d=0.3226 shows a small value of -2±2P/°C. As the value of C increases, εT. K, and for c>0.045, εT. K becomes negative and Q (Q=1/Tanδ) decreases significantly. Therefore, when c>0.045, the same tendency occurs regardless of the composition of any combination of A, b, and d, and this is excluded from the present invention. a≦0.04, a≧0.50, . b≦0.052, b
≧0.65, C>0.045, d≦0.29, d≧0.
With a combination of composition ratios in the range of 60, in addition to a decrease in Q, εT. Since K becomes large, this is not practically preferable. In addition, within this range, the sintered body becomes susceptible to thermal shock and cracks are likely to occur. As mentioned above, the values of A, b, c, and d are selected appropriately. By holding high Q, we can arbitrarily set positive or negative ε.
T. It is possible to obtain the value of K.

On the other hand, the sintered body can be obtained at a relatively low firing temperature of 1160 to 1250°C, which is economical. As described above, the oxide dielectric material according to the present invention is an excellent material that has extremely small dielectric loss at a low dielectric constant, has a small temperature coefficient of dielectric constant, and can obtain any positive or negative value. I understand that.

Claims (1)

[Claims] 1. An oxide dielectric material consisting of a four-component system of CaO-ZnO-PbO-Nb_2O_5. 2 In an oxide dielectric material consisting of a four-component system of CaO-ZnO-PbO-Nb_2O_5, (CaO)a(Z
When expressed as nO)b(PbO)c(Nb_2O_5)d, the sum of the composition ratios a, b, c, and d of each component system is 1.
and each composition ratio is 0.050≦a≦0.450,
The oxide dielectric material according to item 1, which satisfies the following conditions: 0.10≦b≦0.60, 0.0≦c≦0.035, and the remainder d.