JPS58135688A - Manufacture of magneto-resistance element - Google Patents

Abstract

PURPOSE:To reduce the specific resistance and the dispersion of resistance values and thus increase the magneto-resistance effect, by forming a ferromagnetic alloy thin film on a substrate under a specific condition and heat-treating it. CONSTITUTION:The ferromagnetic material having composition of Ni 70wt% and Co 30wt% is evaporated in the thickness of 1,000Angstrom on the Si oxide film substrate 11, and thus a resistor pattern 12 due to a ferromagnetic thin film is formed. To the resistor pattern 12 due to a ferromagnetic thin film is formed. To the resistor pattern 12, electrode parts 13 and 14 are formed by a conductive material evaporation, etc. using a mask pattern, and a heat treatment is performed at 450 deg.C for 30min. The heat treatment is performed in the atmosphere of inert gas or reduction gas. A protection film 15 is formed on the resistor pattern 12 and the electrode parts 13 and 14, and accordingly the magneto-resistance element is obtained. When the content of Ni becomes larger than 91wt% and smaller than 38wt%, and then of Co becomes larger than 62wt% and smaller than 9wt%, the rate of resistance value changes suddenly decreases. When the alloy film thickness becomes thinner 400Angstrom and thicker than 1,200Angstrom , the output decreases, and therefore the significant difference of the dispersion of the rate of resistance value changes (output) and resistance values is not found within heat treatment temperatures 310-550 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetoresistive element having stable magnetoresistive characteristics.

In conventional magnetoresistive elements, the substrate is heated to a temperature of 250°C or less, and nickel (Ni) is applied to the heated substrate.
- It was constructed by depositing a cobalt (Co) alloy to a suitable thickness. In this case, from the viewpoint of ease of operation, strength, etc., the thickness of the alloy film is 2000× or more, and the deposited bale of this alloy film is not heat-treated.

However, the magnetoresistive element constructed by such means is
Due to the structure of the vacuum equipment, the temperature during evaporation is low at 250℃ or less, so defects during evaporation may remain on the round lid-coated alloy film that is formed, increasing the resistivity or decreasing the resistance value. There is also a tendency for the dispersion of Furthermore, the magnetoresistive effect, which is most important for magnetoresistive elements, was also small.

This invention was made in view of the above-mentioned points, and the purpose is to increase the magnetoresistive effect by particularly reducing specific resistance and variation in resistance value, so that it can be effectively used as various magnetic centimeters. The purpose is to provide a method for manufacturing a magnetoresistive element, in which a ferromagnetic alloy thin film consisting of 91 to 38% by weight of nickel and 9 to 62% by weight of Pupart is deposited on a substrate.
Formed with a thickness of 00X to 1200mm, and then
The material is heat treated at a temperature of 50°C.

An embodiment of this invention will be described below. First, as shown in FIG. 1, nickel (N
i) A ferromagnetic material having a composition of 70% by weight and 30% by weight of cobalt (Co) is deposited to a thickness of 1OOOX to form a resistor/f turn 2 made of a ferromagnetic thin film. Then, the electrode portion 13.1 is formed by vapor deposition of a conductive material using a mask pattern for the resistor/quantity turn 12.
4 is formed and then heat treated at 450 DEG C. for 30 minutes. In this case, the heat treatment is carried out in an atmosphere of inert gas or reducing gas. And resistor pattern 1
2. A protective film 15 is formed on the electrode portions 13 and 14 to complete the magnetoresistive element.

Comparing the characteristics of the magnetoresistive element manufactured in this manner and the magnetoresistive element manufactured by the conventional manufacturing method, the results are as shown in Table 1. By manufacturing a magnetoresistive element using the method shown in Figure 2, the specific resistance becomes approximately 1/2, the variation in resistance value becomes less than IA, and the rate of change in resistance value, that is, the output, increases by more than 25 -, which is a very good result. It is confirmed that it is possible to manufacture a magnetoresistive element with these characteristics.

Here, the alloy composition of the ferromagnetic material constituting the resistor/turn 12 is experimentally shown as shown in FIG. This is nickel (Nt) and copal (Co)
This shows the relationship between alloy composition and resistance value change rate (output), where nickel is greater than 91% by weight and less than 38% by weight, and cobalt is greater than 62% by weight and less than 9% by weight. It is confirmed that the rate of change in resistance value decreases rapidly.

Figure 3 shows the resistance value change rate (output) when the film thickness is 10001 and the resistance value change rate (resistance value change rate (output)) when the film thickness is 10001. ) When the alloy film thickness is thinner than 400X or thicker than 1200X, the output becomes small, and an effective resistance change rate (output) can be obtained with a film thickness of 400X to 1200X.

Furthermore, FIG. 4 shows the heat treatment temperature after forming the resistor/turf 12, the resistance value change rate (output) at the treatment temperature of 450°C, and the R
It shows the percentage of resistance value change rate (output) R when 450 is the standard.
When the temperature is higher than 50°C, the output decreases rapidly. Also, 3
Below 00℃, the variation in resistance value is between 300℃ and 55℃.
It was confirmed that the temperature was 2.5 times larger than that at 0°C. That is, no significant difference in the rate of change in resistance value (output) or variation in resistance value is observed between the heat treatment temperatures of 310°C to 550°C.

Next, an example of WN2 will be described in accordance with the experimental results shown in FIGS. 2 to 4 above. That is, in this example, nickel (Ni) 45. A strong abrasive material having a composition of 11% and 55% cobalt (Co) is deposited to a thickness of 600X to form a resistor/transformer. Then, an electrode portion is formed on this resistor/metal turn in the same manner as in the previous embodiment, and heat treatment is performed at 350° C. for 1 hour to produce a magnetoresistive element.

When we measured the resistance change rate (output) of the magnetoresistive element manufactured in this way, it was more than 15 inches larger than the conventional one, and the variation in resistance was less than IA. The characteristics as a magnetoresistive element were significantly improved.

As described above, by manufacturing a magnetoresistive element using the manufacturing method of the present invention, not only can the resistivity be sufficiently reduced, but the rate of change in resistance value (output) can also be increased by 15 inches or more, and the variation in resistance value can be reduced to less than IA. The condition has been improved. Therefore, this magnetoresistive element can be effectively used as various magnetic sensors, and can be effectively applied as a measuring means for automatic control.

[Brief explanation of the drawing]

Fig. 1 shows the structure of a magnetoresistive element manufactured according to the present invention, and Figs. 2 to 4 show the relationship between alloy composition, alloy film thickness, heat treatment temperature, and resistance value change rate (output), respectively. It is a curve diagram. DESCRIPTION OF SYMBOLS 11... Substrate, 12... Resistor arm turn, 13 degrees 14... Electrode part, 15... Capture membrane.

Claims (1)

[Claims] Nickel 91-38% by weight, cobalt 9-9% by weight based on the substrate
A ferromagnetic alloy thin film consisting of 4001-12 weight
001 (11) A method for producing a magnetoresistive element having the special mission of heat-treating the element in a temperature range of 310° C. to 550° C. in an atmosphere of an inert gas or a reducing gas.