JPH077722B2 - Resistor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heating resistor in a thermal head or the like.

[Outline of Invention]

This invention provides a high-performance resistor by using a composite material composed of boron carbide and carbon as a resistor material in a heating resistor used for a thermal head or the like.

[Conventional technology]

Conventionally, thin film resistors formed by vapor phase plating or printing / baking have been used as resistors used in thermal heads, etc., but tantalum nitride, nichrome, ruthenium oxide, etc. have been used as these thin film resistor materials. .

[Problems to be Solved by the Invention]

With respect to the heating resistor in a thermal head or the like, it is desired that the precision and stability of the heating resistor be improved with the recent development of the electronic industry. However, conventionally used resistor materials have problems with respect to the resistivity itself, changes in the resistivity due to temperature, reproducibility and reliability. For example, a metal such as nichrome or tantalum or an infiltration type metal compound such as tantalum nitride or titanium carbide exhibits metal-type electric conduction, and therefore has a low specific resistivity and is used as a thin film resistor. ,
The wiring had to be thin and long. For this reason, the yield in the case of manufacturing the resistor is lowered, and the reliability is also lowered. Further, in such a resistor material, a large increase in the specific resistance caused by a temperature rise due to the application of electric power causes a deviation from the originally intended resistance value.

In addition, ruthenium oxide and tantalum-silicon oxide-based resistors cannot be applied to materials that require high reliability in order to exhibit extremely unstable resistivity due to electrical conduction due to oxygen defects. It was

[Means for Solving the Problems]

In order to solve the above problems, in the present invention, a composite material composed of boron carbide and carbon is used as a resistor.

[Action]

As described above, by using a composite material composed of boron carbide and carbon as the resistor material, it is possible to obtain a resistor having a higher specific resistance than that of metallic electric conduction and a small change in specific resistance with respect to temperature change. You can In general, the resistivity of carbon (graphite) at room temperature is on the order of 10 ° Ωcm, which is a preferable value for a heat-generating thin film resistor, but the physical properties are greatly changed depending on the manufacturing method. In addition, physical vapor deposition (PV
D) and carbon (graphite) thin films made by chemical vapor deposition (CVD) have extremely poor film quality and adhesion to the substrate. However, composite materials made by dispersing electrically conductive carbon (graphite) at the molecular level in boron carbide are almost the same as those in which the relationship between the temperature and electrical resistance of boron carbide shows a semiconductor-like behavior. Electric resistance is not affected by temperature, and the specific resistance value is
Since it is about 1 to 3 orders of magnitude higher than that of interstitial metal nitrides and carbides that have been widely used, when used as a thin film resistor, the length, thickness, and film thickness of the wiring can be set within a highly reliable range. Therefore, it becomes an extremely excellent thin film resistor.

A composite material consisting of boron carbide and carbon has 50
If it is more than mol%, it becomes a semiconductor and the resistivity of the film is
As shown in Fig. 4 (boron carbide: 49 mol%, carbon: 51 mol%), the temperature dependence is large, and when the content of boron carbide is less than 10 mol%, the carbon content increases and the oxidation resistance deteriorates. It is suitable that the content of boron carbide is 10 to 45 mol%.

Furthermore, by changing the composition ratio of boron carbide and carbon, the specific resistance value can be arbitrarily set, and this is a very effective resistor material in resistor design.

〔Example〕

 Embodiments according to the present invention will be described below with reference to the drawings.

[Example-1] As an example of the present invention, a composite film produced by a direct electric heating method and a chemical vapor deposition (CVD) method will be described.

FIG. 1 shows an example of a resistor manufacturing apparatus according to the present invention.
It is a longitudinal cross-sectional view of a CVD apparatus.

First, the vacuum chamber 1 was evacuated to 10 ⁻³ Torr, and then hydrogen, methane and boron trichloride were introduced so that the pressure in the vacuum chamber 1 became 100 Torr. The flow rate of each gas at this time was as follows. Further, the carbon substrate 2 which is a substrate,
An alternating current was applied so that the temperature reached 1400 ° C.

(Gas flow rate condition) Hydrogen ・ ・ ・ 100 cc / min Methane ・ ・ ・ 100 cc / min Boron trichloride ・ ・ ・ 300 cc / min When a film was formed for 1 hour, the film thickness on the carbon substrate 2 was 0.
A composite film having a composition of 2 mm, boron carbide 38.7 mol% and carbon 61.3 mol% was formed.

Fig. 2 shows the results of measuring the change in resistivity with temperature by shaving off the carbon to form a plate-like product. As the resistivity, commonly used interstitial metal carbides and nitrides are used. It was found to be the most suitable heat-generating resistor for thermal heads, etc., because the resistivity change with temperature was about 100 times smaller than that of the product.

[Example-2] As another example of the present invention, a composite film of boron carbide and carbon produced by reactive ion plating will be described.

FIG. 3 is a vertical cross-sectional view of a reactive ion plating device which is an example of a resistor manufacturing device according to the present invention.

First, the vacuum chamber 3 was evacuated to 10 ^-6 Torr and then boron 4 was added in an acetylene (C ₂ H ₂ ) partial pressure of 7 × 10 ^-4 Torr.
Is heated by the hollow cathode type electron beam evaporator 5.
Evaporated and further ionized to form a discharge plasma. After stabilization, the shutter 6 was opened, and reactive ion plating was performed for 5 minutes.
A composite film of Å boron carbide and carbon was formed.

When the relationship between the temperature and the specific resistance of this sample was investigated, it was confirmed that the sample showed the same tendency as in Example-1 and could be used as a precise heating resistor in a thermal head or the like.

[Example-3] Next, the present invention will be described with reference to Examples using reactive high-frequency sputtering as a manufacturing method.

First, evacuate the vacuum chamber to 1 × 10 ^-6 Torr and then
The target surface is cleaned by introducing argon gas so that the concentration becomes × 10 ^-3 Torr and pre-sputtering the surface of boron sufficiently, and further cleaning the target surface by reverse sputtering the glass substrate. Was made.

Next, gas was introduced so that the partial pressure of argon was 1 × 10 ⁻³ Torr and the partial pressure of acetylene (C ₂ H ₄ ) was 1 × 10 ⁻³ Torr. At this time, high-frequency power of 300 W was applied to the target in order to maintain the discharge. After stabilization, open the shutter to form a film on the glass substrate, which is the substrate 2000
A composite film of Å boron carbide and carbon was formed.

Similar to Example-1, the one produced by this method also showed a small temperature dependence of the specific resistance and a high specific resistance value.

[Advantages of the Invention] According to the present invention, by using a composite material of boron carbide and carbon, it is possible to increase the specific resistance as compared with conventional interstitial metal carbides and nitrides, and the ratio with respect to temperature. It has become possible to reduce the dependency of the resistivity. As a result, it can be applied to a fine heating resistor such as a thermal head as a highly reliable and stable resistor material. In other words, by increasing the specific resistance, it is not necessary to increase the thin thickness of the thin film resistor that is the heat generating part, and it is not necessary to intentionally reduce the wiring width. Also in this case, it is possible to significantly improve the yield in the photolithography process and the like as compared with the related art.
Furthermore, since the temperature dependence of the specific resistance is small, high-speed temperature control can be realized.

In the examples, as the method for producing the composite material resistor of boron carbide and carbon according to the present invention, the PVD method, the reactive ion plating method and the reactive sputtering method are mentioned, but other methods such as the sputtering method are used. A method of forming a resistor by using the composite material of boron carbide and carbon of the present invention as a target material, using a plasma CVD method, or making a powder of this material itself into a paste, and performing printing / firing to obtain a resistor. Although it is possible,
It goes without saying that any of these can be expected to have the same effects as the methods described in the examples.

[Brief description of drawings]

FIG. 1 shows an example of a resistor manufacturing apparatus according to the present invention.
FIG. 2 is a vertical cross-sectional view of the CVD apparatus, FIG. 2 is a view showing the relationship between the temperature and the resistivity of the resistor produced in Example-1, and FIG. 3 is an example of the resistor producing apparatus of the present invention. Longitudinal sectional view of the ion plating device of the ion plating method, Fig. 4 shows boron carbide (49 mol%) and carbon (51 mol%)
It is a figure which shows the temperature of the composite film of FIG. 1 ... vacuum tank 2 ... carbon substrate 3 ... vacuum tank 4 ... boron 5 ... hollow cathode electron beam evaporator 6 ... shutter 7 ... substrate

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mizuaki Suzuki 6-31-1, Kameido, Koto-ku, Tokyo Seiko Denshi Kogyo Co., Ltd. (56) Reference JP-A-63-289801 (JP, A)

Claims (1)

[Claims] 1. A heating resistor comprising boron carbide and conductive carbon, wherein the content ratio of boron carbide as a constituent material is 10 to 45% in terms of molar ratio.