JPH02267979A - Manufacturing method of magnetoelectric conversion element - 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] [Industrial Field of Application] The present invention relates to a method for manufacturing a magnetoelectric transducer, and specifically relates to a method for manufacturing a magnetoelectric transducer, and specifically
This invention relates to a technique for improving the mobility of nSb films.

[Background technology]

As a technology to improve the mobility of 1nSbg,
Conventionally, the following methods are known.

After forming In5bi on the surface of the substrate by the three-temperature method, an insulating film made of SiO□ and SiN is formed on the InSb film to cover the InSb film. Heat treatment is performed at a heat treatment temperature for a long time (5 hours or more).

[Problem to be solved by the invention]

According to the above heat treatment method, the mobility of the InSb film can be improved, but this method has the following drawbacks.

In this heat treatment method, heat treatment must be performed at a relatively high heat treatment temperature of 300°C or higher, so In5
If an insulating film is formed on the InSb film and heat treated after forming an electrode on the BL, cracks will occur between the electrode and the InSb/Il due to the difference in thermal expansion coefficients, resulting in disconnection. There is. In order to avoid this problem, it is necessary to form an electrode on the InSb film after the heat treatment as described above, but since the InSb film is covered with an insulating film after the heat treatment, the insulating film cannot be formed after the heat treatment. InSb
It was necessary to peel it off from the film, and this peeling work was difficult.

Further, since the heat treatment time is relatively long, 5 hours or more, it is not suitable for mass production.

The present invention has been made in view of the drawbacks of the conventional methods described above, and its purpose is to improve the mobility of an InSb film by heat treatment at a relatively low temperature and for a relatively short time. The goal is to find ways to solve problems such as those mentioned above.

[Means to solve the problem]

For this reason, the method for manufacturing a magnetoelectric transducer of the present invention includes spin-coating a protective film on the InSb film formed on the surface of the substrate using the SOG coating method, and performing heat treatment at a heat treatment temperature of 220 to 260°C for 90 minutes or more. It is characterized by

[Effect]

The present invention can increase the mobility of the InSb film by forming an insulating layer on the InSb film and subjecting it to heat treatment, thereby increasing the magnetic sensitivity of the magnetoelectric transducer. Moreover, heat treatment can be performed at a relatively low heat treatment temperature of 220 to 260°C using a protective film formed by the SOG (spin-on-glass) method.
Even if heat treatment is performed after forming electrodes on the film, InSb
There are no cracks between the membrane and the electrode. therefore,
There is no need to peel off the protective film from In5bp after heat treatment, and the manufacturing process of the magnetoelectric transducer can be simplified.
Furthermore, by leaving a protective film even after heat treatment,
It can be used to protect b-films and electrodes.

Furthermore, by using an insulating layer formed by the SOG method, the heat treatment time is 90 minutes or more, for example, 90 to 12 minutes.
Since the time can be shortened to approximately 0 minutes, it is also excellent in mass production of magnetoelectric conversion elements.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, AQ20. An insulating film 6 is formed, the substrate temperature is maintained at 480 to 520°C, and the deposition rate ratio (In:S
An InSb film 2 is deposited on the insulating film 6 at a ratio of b=>1:3 to 1:4. After etching this InSb film 2 to form a Hall element 4 and forming an electrode 5 on the Hall element 4, an OCD manufactured by Tokyo Ohka Co., Ltd.
TYPE 2 (#59000) was spin-coated by the SOG method to form a protective film 3.

This sample was heat-treated in an N2 atmosphere (which may contain 0 to 6% 0□) by varying the heat treatment temperature and heat treatment time, and the changes in mobility and carrier density were measured for each. The results shown in Figure 2 (aHb) and Figure 3 (a>(b) were obtained. Figure 2 (a) (b)
The heat treatment time was 2 hours and the heat treatment temperature was approximately 150℃.
Rate of change in mobility Δ when changing from °C to 300 °C
It shows μ(X) and the rate of change in carrier density Δn (%). As is clear from Figure 2(a), the mobility is 22
The maximum temperature is between 0°C and 260°C. On the other hand, the second
As shown in figure (b), this temperature range (220-260
℃), the carrier concentration shows almost no change, and Figures 3(a) and 3(b) show the rate of change in mobility Δμ( X) and carrier density change rate Δn (X
) is shown.

As shown in FIG. 3(a), the mobility continues to increase until the heat treatment time reaches 90 minutes, but when the heat treatment time exceeds 90 minutes, the mobility reaches its maximum value and no increasing trend is observed after that. On the other hand, as shown in FIG. 3(b), as the heat treatment time increases, the carrier density shows a gradual increasing tendency, but when the heat treatment time exceeds 90 minutes, the rate of increase becomes gradual. Therefore, based on this experiment, the InSb film spin-coated with a protective film by the SOG method was heat-treated at a temperature of 220 to 26°C.
0°C, heat treatment time 90 minutes or more (preferably 90-180
It has been revealed that by performing heat treatment under the conditions of 200 min), the mobility can be increased by nearly 20% without significantly changing the carrier concentration. Therefore, heat treatment for increasing mobility can be performed at a relatively low heat treatment temperature and in a short heat treatment time. Note that this heat treatment step can also serve as a protective film forming step. Further, since the heat treatment temperature is 300° C. or lower and N2 gas is sufficient as the atmospheric gas, a normal clean oven can be used for the heat treatment.

(Example 1) An InSb vapor deposition film was formed on a mirror-polished Ni--Zn ferrite substrate by a three-temperature method. The temperature of the substrate at this time was 490° C., and the deposition rate ratio of In and sb was kept at a constant ratio of 1:3 to 1:4. In thus obtained
Tokyo Ohka OCD TYPE2 (#590
00) was spin-coated by the SOG method. After this, N2
90℃, 30 minutes in atmosphere → 150℃, 30 minutes -250
Heat treatment was performed through a preheating step at ℃ for 2 hours.

As a result, the mobility of the InSb film was 25,
After heat treatment, the mobility increased from 000 cm"/V-sec to 30,000 cm"/V-sec, resulting in an improvement of nearly 20%.

(Second example) An InSb vapor deposition film was formed on a mirror-polished Nj-Zn ferrite substrate by a three-temperature method. The temperature of the substrate at this time was 490°C, and the deposition rate ratio of In and sb was 1:3.
A constant ratio of 1:4 was used. Next, this InS
The B film was etched by photoetching to form a Hall element pattern, and electrode metal was deposited on predetermined positions of the Hall element pattern to form electrodes. After this,
Tokyo Ohka OCD TYPE2 (#59000) I
The entire substrate was spin-coated over the nSb film and Hall element by the SOG method. After this, in a clean oven at 90°C in a N2 atmosphere (containing about 6% residual 02).
, 30 minutes → 150℃.

Heat treatment was performed through a preheating step of 30 minutes → 250° C. for 2 hours. As a result, the Hall voltage was 9011v before heat treatment.
/v-KG, but after heat treatment it became 109mV/V
-Increased to KG. Furthermore, the percentage of devices with an unbalanced voltage of ±7 mV or less increased from 80% to 85% of the total.

In this way, the unbalanced voltage is reduced and the variation is also reduced, so the yield rate is improved. Furthermore, changes in characteristics during environmental tests (especially heat resistance tests) were also reduced. Further, even after heat treatment, no cracks were observed between the electrode and the In5b film. Therefore, it was possible to obtain a Hall element in which the InSb film and electrodes were protected by a glassy protective film.

〔Effect of the invention〕

According to the present invention, the mobility of the InSb film can be improved, and the magnetic sensitivity of the magnetoelectric transducer can be made higher. Moreover, since the heat treatment temperature in the manufacturing process can be lowered, even if the electrode is formed on the InSb film and then covered with a protective film and heat treated, no cracks will occur between the electrode and the InSb film, improving the yield rate. There is no need to #IM the protective film after heat treatment.
It can be used to protect 5bJli and electrodes, and the manufacturing process can be simplified. Furthermore, the heat treatment time can be made shorter than before, and mass productivity is improved.

[Brief explanation of drawings]

Figure 1 is an enlarged cross-sectional view of a part of the magnetoelectric conversion element of the present invention, and Figures 2 (a) and (b) are graphs showing the rate of change in mobility and the change in carrier concentration when the heat treatment temperature is changed. FIG. 3 (aHb) is a graph showing the rate of change in mobility and a graph showing the rate of change in carrier concentration when the heat treatment time is changed. 1... Substrate 2... InSb film 3... Protective film first side Figures (a) (b) Heat treatment temperature ('C) Figures (a) (b) Heat treatment time (min>

Claims (1)

[Claims] (1) A method for producing a magnetoelectric transducer element, which comprises spin-coating a protective film on an InSb film formed on a substrate surface by an SOG coating method, and subjecting it to heat treatment at a heat treatment temperature of 220 to 260°C for 90 minutes or more. .