JPS5918627A - Semiconductor porcelain condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor porcelain capacitor, and an object of the present invention is to provide a capacitor using a porcelain material and having a capacitance comparable to that of an electrolytic capacitor.

Ceramic capacitors can be roughly divided into general ceramic capacitors and semiconductor ceramic capacitors, and when classified by shape, they are disc-shaped,
Available in square plate shape and cylindrical shape. In terms of capacitance, disk-shaped semiconductor capacitors have a large capacitance of about 0.2 to 0.3 μF.

As is well known, in a surface reoxidation type semiconductor ceramic capacitor, the inside of the element is a semiconductor and the surface is a dielectric layer, and the thinner the dielectric layer, the greater the capacitance. The normal thickness is about 1 to 30 μm.

The present invention realizes a large-capacity ceramic capacitor by effectively utilizing this surface reoxidation type structure and creating a completely new honeycomb shape capacitor. This honeycomb-shaped porcelain element is composed of a semiconductor porcelain material whose surface is mostly covered with a dielectric layer, and a nickel-plated electrode or a silver electrode is placed on the dielectric layer, and one counter electrode is made of semiconductor material. A nickel-plated electrode is provided on the part.

The part that contributes to the capacitance is the part of the dielectric layer below the electrode, and the semiconductor part of the honeycomb element serves as a counter electrode and reinforcing material for the second electrode of the dielectric layer.

Therefore, in the capacitor of the present invention, the area of the honeycomb-structured reservoir electrode is extremely large, the dielectric constant is extremely large because the surface reoxidized semiconductor material is used, and the thickness of the dielectric layer is extremely thin. This makes it possible to obtain an extremely large capacity.

The electrodes, which are important points in this honeycomb capacitor, will be described below.

The electrodes of the semiconductor part must be ohmic electrodes suitable for N-type semiconductors, ohmic silver electrodes, two sockets/I
/ electrode, and other electrodes were considered, but the nickel (nickel) V electrode was the most suitable in terms of characteristics and practicality. On the other hand, it has been found that the electrodes on the dielectric layer may be ordinary silver electrodes or nickel electrodes.

Next, an example will be given and explained.

Example 1 Starting material: 0.91 Ba Tl 03 + 0.09
Nd匈TiOs+O,oo3Mn02 (Mo/L/) was mixed in the composition ratio, pre-fired according to the usual ceramic manufacturing method, and the powder obtained by pulverization was formed into a honeycomb. After calcination at 1300°C for 2 hours at
Secondary firing for 1 hour and then 1 hour at 1000℃ in air.
Tertiary firing for an hour. The structure of the obtained device has an external size of 10 ×
It is a square column of 10wL x 10mm, and the hole is a square of 1.6mm x 1.6mm, and the wall thickness between the holes is 0.4 knots. One side of this device with holes was polished to expose the semiconductor portion, and a nickel plated electrode (j) was formed there.For comparison, a sample with an ohmic silver electrode was also prepared. Then, silver electrodes were formed on the dielectric layer in both of the above-mentioned two series elements.

FIG. 1 is a perspective view of the capacitor manufactured as described above, and FIG. 2 is a cutaway perspective view of the main parts thereof. In the figure, 1 is a semiconductor portion of a honeycomb-shaped ceramic element, and a dielectric layer 2 is formed on most of its surface by reoxidation. 3 is a nickel-plated electrode, which is formed on the surface of a honeycomb-shaped ceramic element by polishing one open side thereof. A silver electrode 4 is formed on the dielectric layer 2. In addition, in the comparative element, the nickel plated electrode 3 was replaced with a silver electrode.

The characteristics and life test results of these two elements are shown in Table 1 in comparison. The life test was carried out at a temperature of 60℃, a relative temperature of 96℃,
A humidity resistance load test was conducted in which an applied voltage of 60 V (DC) was continuously applied.

Table 1 Example 2 A sample in which the semiconductor portion of a honeycomb element obtained by the same procedure as in Example 1 was nickel-plated, and a sample in which a non-ohmic silver electrode was further applied to the nickel-plated layer. Two types were made and their characteristics were measured. The results are shown in Table 2.

As can be seen from Table 1, the element having the nickel plated electrode on the semiconductor portion has a larger capacity than the silver electrode element. This shows that the nickel plated electrode is a good ohmic electrode, whereas silver is very difficult to become a completely ohmic electrode. In a life test, the properties of the nickel-plated electrode element hardly change, whereas the properties of the silver electrode element deteriorate significantly. This is thought to be due to oxidation of the interface between the element body and the silver electrode.

As can be seen from Table 2, even if a silver electrode is placed on top of a nickel plated electrode, there is no significant difference in overall characteristics.

As described above, the capacitor of the present invention has a large capacity and stable characteristics, is highly mass-producible, and is less expensive than currently used elements of the same capacity. Note that the outer shape of the honeycomb element, the shape of the holes, etc. can be arbitrarily determined depending on the application and the like.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a semiconductor ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a cutaway perspective view of the main parts thereof. 1... Semiconductor portion, 2... Dielectric layer,
3, 4... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] One electrode is provided on the semiconductor portion of the surface reoxidized semiconductor ceramic honeycomb element having a dielectric layer on the surface, and the other electrode is provided on the dielectric layer, and the one electrode is made of nickel. A semiconductor ceramic capacitor characterized by being an electrode.