JP2727232B2 - Magneto-optical recording medium and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium in which a Si-based dielectric is coated on one or both sides of a magnetic film as an enhancement film and a protective film, and a method for manufacturing the same.

(Prior art) Conventionally, as this type of magneto-optical recording material, a transparent and high-refractive-index Si-based dielectric material such as SiN _x , SiO _x , SiN _x O _y is provided on one or both sides of a magnetic film made of, for example, TbFeCo. Coated films are known.

Further, as a method for manufacturing a magneto-optical recording medium, the target material is sputtered by reactive sputtering in an atmosphere containing a reactive gas such as using a Si-based target for example N _2, the reaction of the sputtered target material It is known to form a Si-based dielectric film on one or both sides of a magnetic film made of, for example, SiN _X by reacting with a gas.

(Problems to be Solved by the Invention) The magnitude of the internal stress of the Si-based dielectric film affects the tilt angle of the Si-based dielectric, and the higher the internal stress, the larger the tilt angle. In addition, a large tilt angle causes a servo failure of the head and erroneous reading of a signal.

However, since the Si-based dielectric film formed by the above method is generally of high purity, it has a high internal stress, and as a result, the tilt angle becomes large, causing a servo failure of the head or erroneous reading of a signal. There are problems such as.

Further, if the internal stress of the film to be formed is large, the target material attached to the periphery of the cathode or the like in the film forming apparatus during sputtering is likely to peel off, and the target material is scattered into the film forming apparatus during film formation. However, there is a problem that this adheres to the Si-based dielectric film being formed on the substrate and causes dust.

Therefore, a magneto-optical recording medium provided with a Si-based dielectric film having low internal stress has been demanded.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magneto-optical recording medium having a Si-based dielectric film having a low internal stress and a method for manufacturing the same.

(Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventors have found that the internal stress is reduced by mixing impurities into the Si-based dielectric film.

The magneto-optical recording medium of the present invention is based on the above findings, and is formed on one side or both sides of a magnetic film.
It is characterized in that P is contained in a Si-based dielectric film at 10 ¹⁴ atoms / cm ³ or more.

In the present invention, the content of P in the Si-based dielectric film is set to 10 ¹⁴ at.
The reason for setting it to oms / cm ³ or more is that if the P content is less than 10 ¹⁴ atoms / cm ³ , the effect of lowering the internal stress of the film cannot be obtained.

Further, a method for manufacturing a magneto-optical recording medium is a method of forming a Si-based dielectric film on one or both sides of a magnetic film by a reactive sputtering method using a Si-based target material. It is characterized by using a Si-based target material doped with ¹⁴ atoms / cm ³ or more.

The P-doped Si-based target material used in the method of the present invention is
The P material may be doped into the Si target material or the target material obtained by adding Al or the like to Si by a known dissolving method, and the P doping amount in the target material may be adjusted by the solubility. Is generally 10 ¹⁴ to 10 ²⁰ atmos / cm
^{About 3}

As the reactive sputtering method, N ₂ gas, O ₂ gas,
An RF sputtering method and a DC sputtering method using a reactive sputtering gas such as N ₂ + O ₂ gas are exemplified. The sputtering gas pressure for sputtering the target material is 1 × 10 ^-3 to 1
Set to about × 10 ^-1 Torr.

(Operation) By including P in the Si-based dielectric film at 10 ¹⁴ atoms / cm ³ or more, P enters into the network of Si, etc., thereby relaxing the strain of the film and lowering the internal stress.

By using a Si-based target material doped with P at 10 ¹⁴ atoms / cm ³ or more, the P content in the Si-based dielectric film formed by the reactive sputtering method is adjusted.

(Example) Next, a specific example of the present invention will be described.

Experimental Example 1 In a N ₂ gas atmosphere as a reaction gas, P was added to Si (purity: 99.999%) as a target material at 10 ¹⁴ atoms / cm ³ and 2 × 10 ¹⁵ a.
Each target material is sputtered by an RF sputtering method using a Si-based target material doped with toms / cm ³ and 2 × 10 ¹⁹ atoms / cm ³ , respectively, and a 900-nm-thick SiN _X P _Y film (hereinafter referred to as a Si-based dielectric material). A film was formed to form a magneto-optical recording medium.

The P content (atoms / cm) in each of the formed Si-based dielectric films
³ ) was measured by secondary ion mass spectrometry. The results obtained are shown in FIG.

The sputtering gas pressure was 1 × 10 ⁻² Torr, the sputtering power was 2.2 KW, and the deposition rate was 500 ° / min. Incidentally, the refractive index n of the Si-based dielectric film formed on the substrate is
Adjusted to 2.3.

As is clear from FIG. 1, the P doping amount in the Si-based target material and the P content in the Si-based dielectric film formed on the substrate show almost the same value. Therefore, since the amount of P dope in the target material and the amount of P in the formed Si-based dielectric film are in a proportional relationship, the amount of P-doped Si film in the target material is not proportional to the amount of P in the target material. It was confirmed that the P content could be adjusted.

Experimental Example 2 The internal stress of each magneto-optical recording medium prepared in Experimental Example 1 was measured by measuring the deformation of a thin cover glass substrate. The results obtained are shown in FIG.

Comparative Experimental Example 1 An Si-based dielectric film was formed in the same manner as in Experimental Example 1 except that a target material containing only Si (99.999% purity) (a target material not doped with P at all) was used as the target material. .

The internal stress of the prepared Si-based dielectric film not containing P was measured in the same manner as in Experimental Example 2. The results obtained are shown in FIG.

As is apparent from FIG. 2, P is 10 ¹⁴ in the Si-based dielectric film.
By containing atoms / cm ^3, the internal stress of the conventional Si-based dielectric film containing no P at all -3.5 × 10 ⁹ dy
The internal stress is reduced to −8 × 10 ⁸ dyn / cm ² compared to n / cm ² ,
Further, as the P content increased, the internal stress also tended to decrease, and when the P content reached 10 ¹⁵ atoms / cm ³ or more, the internal stress tended to be substantially constant. Especially Si
By containing 5 × 10 ¹⁵ atoms / cm ³ of P in the system dielectric film, the internal stress was reduced by one digit or more as compared with the conventional Si system dielectric film containing no P at all. Therefore, it was confirmed that the internal stress of the Si-based dielectric film was reduced by including P at 10 ¹⁴ atoms / cm ³ or more.

It was confirmed that the same effect could be obtained by using a target material in which Si · Al was doped with P at 10 ¹⁵ atoms / cm ³ instead of the target material in which Si was doped with P.
Further, the reaction sputtering gas in place of the N ₂ gas O ₂ gas, N ₂ +
It was confirmed that the same effect was obtained even when O ₂ gas was used.

Experimental Example 3 Si doped with 2 × 10 ¹⁵ atoms / cm ³ of P as a target material
A magneto-optical recording medium was prepared in the same manner as in Experimental Example 1 except that a DC sputtering method (sputter power: 3 KW) was used as the sputtering method, using a system target material. When the internal stress of the Si-based dielectric film of the created magneto-optical recording medium was measured by the same method as in Experimental Example 2, the internal stress of the film was −1.6 × 10 ⁸ dyn / cm.
^{Was 2} .

Experimental Example 4 Si doped with 2 × 10 ¹⁵ atoms / cm ³ of P as a target material
A 5.25 inch diameter disk made of polycarbonate was used, and a film was formed on one side of the disk.
A 900 mm thick Si-based dielectric film is formed, and an 800 mm thick Tb
A magnetic film made of FeCo was formed, and a Si-based dielectric film having a thickness of 900 mm was further formed to produce a disk medium. The tilt angle of the Si-based dielectric film of the produced disk medium was measured and found to be 3 mrad. The internal stress of the Si-based dielectric film was −4.2 × 10 ⁸ dyn / cm ² .

Comparative Experimental Example 2 The target material used was a single Si target material not doped with P at all, and had a diameter of 5.
Except that a 25-inch disk was used, the same method as in Experimental Example 4 was used except that a 900-nm thick P-free Si dielectric film and a 800-mm thick TbFeCo magnetic film were formed on one surface of the disk, and a 900-mm-thick magnetic film was further formed. A disk medium was prepared by forming a Si-based dielectric film containing no P at all. Of the created disk medium
When the tilt angle of the Si-based dielectric film was measured, it was 6 mrad. The internal stress of the Si-based dielectric film is −3.5 × 10 ⁹ dy
n / cm ² .

As is clear from Experimental Example 4 and Comparative Experimental Example 2, it was confirmed that the tilt angle of the Si-based dielectric film was reduced by adding P to the Si-based dielectric film.

(Effect of the Invention) As described above, according to the magneto-optical recording medium of the present invention, P is contained in the Si-based dielectric film formed on one or both sides of the magnetic film.
Since 10 ¹⁴ atmos / cm ³ or more is contained, the internal stress can be reduced as compared with a conventional Si-based dielectric film containing no P at all.

In addition, when using the method for manufacturing a magneto-optical recording medium of the present invention, a Si-based target material that is P-doped at 10 ¹⁴ atoms / cm ³ or more is used as the Si-based target material. P in Si-based dielectric film to be formed
The effect is that the content can be easily adjusted, and a magneto-optical recording medium having a low dielectric stress and a dust-free Si-based dielectric film on one or both sides of the magnetic film can be easily manufactured. Have.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing the relationship between the change in the P doping amount in the target material and the P content in the Si-based dielectric film, and FIG. 2 is a graph showing the change in the P content in the Si-based dielectric film and the Si content. FIG. 4 is a characteristic diagram showing a relationship with an internal stress of a system dielectric film.

Claims (2)

(57) [Claims] 1. A magneto-optical recording medium characterized in that P is contained in an Si-based dielectric film formed on one side or both sides of a magnetic film at 10 ¹⁴ atoms / cm ³ or more. 2. A Si system using a target material, reactive by sputtering in a method of forming a Si-based dielectric film on one side or both sides of the magnetic film, P 10 ¹⁴ as the Si-based target
A method for producing a magneto-optical recording material, comprising using a Si-based target material doped with atoms / cm ³ or more.