JP2548704B2 - Magneto-optical disk and its manufacturing method - Google Patents

Description

The present invention relates to a magneto-optical disk for writing (recording), reproducing and erasing information by using a laser beam and the like, and particularly to magnetic and magnetic materials having high corrosion resistance. Durable and highly reliable magneto-optical disk with a magnetic recording film with optical characteristics, and durable with a dielectric film such as a Kerr enhance film and a protective film with few film defects and good adhesion to the underlying layer And a method for manufacturing a magneto-optical disk having high reliability.

[Conventional technology]

In recent years, a magneto-optical disk which can read and rewrite a large amount of information at high speed and with high density has been receiving attention. The magnetic recording material used for this magneto-optical disk is mainly made of an alloy containing a rare earth element and an iron group element, and various materials have been studied. However, these magnetic recording materials are active with respect to the environment in which they are used, and readily react with moisture and oxygen in the air to form hydroxides and oxides on their surfaces. This reaction gradually progresses from the surface of the magneto-optical disk to the inside of the magnetic recording film, which causes a problem that the magnetic and magneto-optical characteristics of the magnetic recording film are significantly deteriorated. This deteriorates the reliability of the magneto-optical disk, which has been a major obstacle to practical use.

To date, as a method of solving the corrosion problem of the magnetic recording film, (1) a method of improving the corrosion resistance of the magnetic recording film itself, (2) a protective film is provided on the surface or interface of the magnetic recording film to shut off the outside air. The method of doing is considered. In particular, if the corrosion resistance of the magnetic recording film itself can be improved as in the former case, the step of providing the protective film becomes unnecessary and the manufacturing process of the magneto-optical disk can be simplified. For this reason, many proposals have been made to improve the corrosion resistance of the magnetic recording film itself, and representative examples thereof are JP-B-60-21217 and JP-B-60-26825. However, there is a contradictory relationship between the improved corrosion resistance of the magnetic recording film and the magnetic and magneto-optical characteristics, and there is no magnetic recording film that satisfies both of them at the same time.

On the other hand, when manufacturing a magneto-optical disk, for example,
In the magneto-optical disk having the structure shown in the figure, on the substrate 26,
A car enhance film 27 is formed and a magneto-optical recording film 28 is formed thereon.
A magneto-optical disk was manufactured by a method in which a protective film 29 was formed on the upper surface of the protective film 29 by a sputtering method or a vacuum evaporation method. However, in the case of forming an enhance film and a protective film mainly composed of the above-mentioned dielectric material, the vacuum deposition method has a weak adhesive force with those underlayers, and the sputtering method destroys or destroys the vicinity of the underlayer surface. There are many problems such as damage and slow film formation, and poor controllability of film formation.

[Problems to be solved by the invention]

Conventionally, in order to improve the corrosion resistance of the magnetic recording film itself,
An element effective for improving corrosion resistance has been added to magnetic recording materials. These additive elements are required to have a condition that the magnetic and magneto-optical characteristics are not deteriorated and the corrosion resistance is improved. However, as described above, the magnetic and magneto-optical characteristics and the corrosion resistance of the magnetic recording film conflict with each other. That is, although the corrosion resistance is improved by the added element, the magnetic and magneto-optical characteristics are deteriorated. On the contrary, if the deterioration of the magnetic and magneto-optical characteristics is suppressed, there is a problem that sufficient corrosion resistance cannot be obtained. On the other hand, the vacuum deposition method used in the prior art has a problem in that the adhesiveness to the underlying layer is weak in the formation of a car enhance film and a protective film mainly composed of a dielectric material that constitutes the magneto-optical disk. Further, the sputtering method has problems such as (1) the underlayer is destroyed by plasma, (2) the film formation rate is slow, and (3) the controllability of the film formation is poor. Furthermore, these film forming techniques have a drawback that the obtained film lacks reproducibility because the controllability of the film formation is poor.

An object of the present invention is to provide a highly reliable and reliable magneto-optical disk having a magnetic recording film with high corrosion resistance without deteriorating magnetic and magneto-optical characteristics, and a method for manufacturing the same.

[Means for solving problems]

The above object of the present invention is to provide a magnetic recording film made of an alloy of a rare earth element and an iron group element, or the above alloy with atomic%
A magnetic recording film made of an alloy containing 10 atomic% or less of at least one element selected from the group consisting of Ti, Ta, Nb, Al, Zr, Ni, Pt, Rh and Pd, and the surface of the magnetic recording film. Selected from the group consisting of P, As, and Se, which are elements that form stable passivation for blocking oxygen or moisture in the atmosphere and elements that improve corrosion resistance that promote oxygen on the surface of the magnetic recording film. At least one element and C, B, Si, Ge, He,
At least one element selected from the group of Ne and H, or at least one element selected from the group of P, As and Se, and selected from the group of C, B, Si, Ge, He, Ne and H At least one element and at least one element selected from the group of Mo, W, Cr, Re, and Ru, or at least one element selected from oxygen and nitrogen are added to the magnetic recording film. Then, the film thickness is achieved by ion-implanting the above element to a depth of 1/2 or less.

In the ion implantation method of the present invention described above, ions are emitted from a target made of the element of the ions to be implanted, and ionization energy of 10 to 50 keV is applied by an accelerator, and 1 × 10 ¹⁶ ions / cm ^{2 to} 3 × 10 ¹⁷ are applied. It is preferable to use an ion implantation amount of pcs / cm ² . In this case, the ion implantation depth in the magnetic recording film can be freely controlled by changing the ion acceleration voltage, and since the ion implantation process is performed at a low temperature, a substrate having low heat resistance such as plastic is used. In addition, ion implantation can be performed with high purity, controllability and reproducibility of the implanted element.

Further, the present invention is a magnetic recording film made of an alloy of a rare earth element and an iron group element, Ti, Ta, Nb, A which is an element that reacts with oxygen or nitrogen to form a stable oxide or nitride.
at least 1 selected from the group consisting of l, Zr, Ni, Cr, Mo and W
At the same time, a metal element of a species and oxygen, nitrogen, or a mixed gas thereof are ion-implanted to a depth of 1/2 or less of the film thickness of the magnetic recording film, or after the above-mentioned metal element is ion-implanted, oxygen is added. , Nitrogen or a mixed gas thereof, by ion implantation to a depth of 1/2 or less of the film thickness of the magnetic recording film, or Ti, which is a stable oxide or nitride forming element described above,
At least one metal element selected from the group consisting of Ta, Nb, Al, Zr, and Ni is contained in the magnetic recording film in an amount of 10 atomic% or less in advance, and oxygen, nitrogen, or a mixed gas thereof is magnetically recorded. The object of the present invention can be achieved by implanting ions to a depth of 1/2 or less of the film thickness.

In the ion implantation method of the present invention, similarly to the above-described method, the implanted ions are emitted from the target, and the ionization energy in the range of 10 to 50 keV is applied by the accelerator.
It is preferable to set the ion implantation amount to × 10 ¹⁶ pieces / cm ^{2 to} 3 × 10 ¹⁷ pieces / cm ² . Then, the conditions for introducing oxygen, nitrogen, or a mixed gas thereof for oxidizing or nitriding the injected ions of the metal element to form a stable oxide or nitride are gas thickness of 1 × 10 ^-2 ~ Ion implantation is preferably performed within the range of 5 × 10 ⁻³ Torr. And
The control of the ion implantation depth of these oxygen, nitrogen or these mixed gas can be controlled freely by changing the acceleration voltage of the ions, and since it is a process that allows ion implantation at low temperature, it can An inexpensive substrate having low heat resistance can be used, and moreover, ion implantation can be performed with good controllability and reproducibility.

Further, the depth of implanting the passivating element, the oxide or nitride forming element into the magnetic recording film of the present invention by the ion implantation method has the effect of improving the corrosion resistance even if the ion implantation depth is very small. However, if the depth exceeds the film thickness of the magnetic recording film, the magnetic and magneto-optical characteristics of the magnetic recording film itself deteriorate, so the ion implantation depth is 1/2 or less of the film thickness of the magnetic recording film. Is preferred.

Furthermore, the present invention is an alloy of a rare earth element and an iron group element, or an alloy of a rare earth element and an iron group element, Ti, Ta, Nb,
At least 1 selected from the group consisting of Al, Zr, Ni, Pt, Rh, and Pd
In a magneto-optical disk having a magnetic recording film made of an alloy containing 10 atomic% or less of various elements, a group of P, As, and Se, which are corrosion resistance improving elements that promote stable passivation or oxidation in the magnetic recording film. At least one element selected from the group consisting of C, B, Si, Ge, He, Ne and H, or at least one element selected from the group consisting of P, As and Se, and C, B, Si, G
At least one element selected from the group of e, He, Ne, and H and at least one element selected from the group of Mo, W, Cr, Re, and Ru is halved in thickness of the magnetic recording film. The method of manufacturing a magneto-optical disk according to the present invention includes at least the step of performing a heat treatment in a gas containing at least one selected from oxygen and nitrogen before or after ion implantation to the following depths. The purpose can be achieved.

Furthermore, in the case of forming a dielectric film such as a car-enhancement film and a protective film of Si ₃ N ₄ , TiN, SiO, SiO ₂ , TiO ₂ which constitute the magneto-optical disk, Si _{3 is used} as a source gas thereof. SiH ₄ and NH _{3 for} N ₄ and T for TiN
iCl ₄ and NH _3, such as SiH ₄ and H _{2 for} SiO and O ₂ or
Such as N ₂ O, in the case of SiO _2, such as SiH ₄ and O _2, in the case of TiO ₂ TiC
low substrate temperature (preferably 90 ° C) using l ₄ and H ₂ O etc.
In the following), for example, laser-excited chemical vapor deposition (L-CV)
The film can be formed by the method D). That is, L-C
According to the VD method, the underlying layer of the dielectric film to be formed is not destroyed or damaged, there are few film defects, the adhesion with the underlying layer is good, and the film formation can be performed at high speed and with good controllability. It is possible to efficiently obtain a highly reliable magneto-optical disk having excellent magnetic and magneto-optical characteristics, excellent corrosion resistance and durability.

[Action]

In the present invention, an element group such as P, As, and Se, an element group such as C, B, Si, Ge, He, Ne, and H in order to form a corrosion-resistant passivation film from the surface to the inside of the magnetic recording film, Mo,
At least one passivating element and surface oxidation promoting element selected from the group of elements such as W, Cr, Re, Ru,
Ions are implanted into the surface layer of the magnetic recording film, or Ti, Ta, Nb, Al, Zr, Ni, Pt, R
When a passivation element such as h or Pd or a noble metal element is contained and a surface oxidation promoting element is ion-implanted into it, the passivation element is concentrated near the surface of the magnetic recording film by the action of this surface oxidation promoting element. These elements become an oxide passivation film on the surface of the magnetic recording film. Since this passivation film densely and uniformly covers the surface of the magnetic recording film, the magnetic recording film is completely shielded from the atmosphere and protected. Further, when the above elements are ion-implanted into the magnetic recording film, the depth of the ion implantation can be freely controlled by the energy of the ion implantation, and the implantation element reaches the recording surface side of the magnetic recording film. Is not reached or the magnetic recording film is not heated, the magnetic and magneto-optical characteristics are not deteriorated and the corrosion resistance can be improved.

Further, in the present invention, elements that form a stable oxide or nitride in advance in the magnetic recording film, such as Ti, T
At least one metal element such as a, Nb, Al, Zr, Ni, Cr, Mo, and W is contained in the magnetic recording film, and oxygen is added to the magnetic recording film.
Whether a gas containing at least one kind of nitrogen is ion-implanted, or the above-mentioned metal element and the above-mentioned gas are simultaneously ion-implanted into the magnetic recording film not containing the above-mentioned oxide or nitride forming element, Alternatively, when the above-mentioned metal element is ion-implanted and then the above-mentioned gas is ion-implanted, a stable dense oxide layer or nitride layer or a mixed layer thereof is formed in the vicinity of the surface portion of the magnetic recording film. Corrosion resistance is remarkably improved because the magnetic recording film is protected by blocking oxygen and moisture therein. On the other hand,
Since the ion implantation depths of the above metal elements and gas can be freely controlled as described above, the depth of the ion implantation layer can be strictly controlled to 1/2 or less of the thickness of the magnetic recording film. Therefore, the magnetic and magneto-optical characteristics of the magnetic recording film are not deteriorated.

Furthermore, in the present invention, a magnetic recording film made of an alloy of a rare earth element and an iron group element, or the above-mentioned passivating element,
The magnetic recording film containing an oxide or nitride forming element, or the magnetic recording film subjected to the above-mentioned ion implantation treatment may be subjected to a heat treatment or a surface treatment in an atmosphere containing oxygen, nitrogen or a mixed gas thereof to obtain the above A dense protective film similar to the above can be formed on the surface of the magnetic recording film, which also improves the corrosion resistance without deteriorating the magnetic and magneto-optical characteristics of the magnetic recording film.

Further, in the case of producing the magneto-optical disk of the present invention, it is necessary to heat the substrate temperature to a high temperature of 400 ° C. or higher in the ordinary chemical vapor deposition method in forming a film such as a car enhance film and a protective film. However, in the present invention, a film is formed at a substrate temperature of 90 ° C. or lower by using a laser-excited chemical vapor deposition method (L-CVD method) using a laser beam having high energy as the excitation energy of the source gas. Therefore, it is possible to use an inexpensive polymer material that does not consider heat resistance as the substrate or the medium constituent material. further,
By using the L-CVD method of the present invention, it is possible to remarkably improve the adhesive force between the underlayer or the substrate without breaking or damaging the underlayer or the substrate surface. Since the L-CVD method can be used to form a film at high speed and with good controllability, a magneto-optical disk can be produced with high reproducibility and high efficiency, and it is highly reliable in terms of corrosion resistance and durability. It is possible to obtain a high-performance magneto-optical disk having excellent properties.

〔Example〕

An embodiment of the present invention will be described below in more detail with reference to the drawings.

(Example 1) A magneto-optical disk was manufactured as follows.
First, a magnetic recording film having a composition of Tb ₂₈ Fe ₆₄ Co ₈ was formed on the washed circular disk substrate to a film thickness of 0.1 μm by a sputtering method. The condition at this time is Ar as discharge gas.
The discharge gas pressure was 5 × 10 ⁻³ Torr, the input RF (high frequency) power density was 1.1 W / cm ² , and the sputtering time was 5 minutes. Then, on the magnetic recording film, Cr, W,
Implant Mo, Re, Ru, then P, B or P, C,
I hit B. The driving depth at this time was 150Å. The characteristics of the magneto-optical disk manufactured in this way are that the Kerr rotation angle θ _k is 0.33 degrees, the coercive force Hc is 4.0 kOe, and the Curie temperature Tc.
Was 200 ° C, and the operating characteristics of this magneto-optical disk were measured, and the C / N (carrier to noise ratio) was 50d.
It was B (laser output 7 mW, external magnetic field 200 Oe). These characteristics did not show any difference as compared with the case of the magnetic recording film only of TbFeCo which did not use the present invention.

Next, a life test of this magneto-optical disk was conducted. The life is evaluated by measuring the change with time of the saturation magnetization and the change with time of the Kerr rotation angle measured from the recording surface side when this disk is stored in a high temperature and high humidity environment with a relative humidity (RH) of 95% at 80 ° C. It was done by doing. The results are shown in FIG. In the figure, the abscissa indicates the storage time (hour), and the ordinate indicates the change rate (%) of the saturation magnetization Ms and the Kerr rotation angle θ _k relative to the initial value of 100. First, TbFeCo
In the case of only, the saturation magnetization Ms increased with the passage of time as shown by the curve 1, and after 500 hours, it increased to about 90% of the initial value. On the other hand, according to the ion implantation method of the present invention
In the case of the TbFeCo film formed by implanting Cr or Mo and P, C or P, C, B, the change in the saturation magnetization Ms was about 5%, which was extremely small, as shown by the curve 3. Also,
The change in the car rotation angle θ _k is 500 when the present invention is not used.
Increased about 20% after hours. In contrast, θ _k of the magneto-optical disk manufactured by the method of the present invention did not change at all.

From the above results, the corrosion resistance of the magnetic recording film for a magneto-optical disk produced by the method of the present invention could be significantly improved as compared with the magnetic recording film produced by the conventional method.

(Example 2) The magneto-optical disk was manufactured in the same manner as in Example 1. Ie, on a cleaned circular disc substrate
A 0.1 μm magnetic recording film having a composition of Tb ₂₈ Fe ₅₉ Co ₈ X ₅ (X = Ti, Ta, Nb, Ni) was formed by the sputtering method.
The sputtering conditions at this time are the same as in Example 1. Subsequently, P, Si or As, Ge, or Se or B was implanted into this magnetic recording film by the ion implantation method. The driving depth at this time was 200Å. The characteristics of the magneto-optical disk manufactured in this way are as follows: θ _k = 0.30 °, Hc = 3.0 kOe, Tc = 180
° C. Moreover, when the operating characteristics of this magneto-optical disk were measured, it was C / N = 51 dB. These characteristics are
No difference was seen from the characteristics of the magneto-optical disk having the magnetic recording film produced without using the present invention.

After measuring the characteristics, a life test of this disk was performed in the same manner as in Example 1. The results are shown in FIG. In the figure, the horizontal axis shows the storage time (hours), and the vertical axis shows the change rate (%) of the saturation magnetization Ms as a relative value when the initial value is 100. First, curves 5 and 6 show changes in the saturation magnetization Ms in the case of the magnetic recording film produced without using the ion implantation method of the present invention. Curve 5 shows TbFeCoNi on the magnetic recording film.
6 is used, the curve 6 is TbFeCoX (X = Ti, Ta, Nb)
Is the case. In the conventional method, T is used to improve corrosion resistance.
When i, Ta, Nb, and Ni are added, the change rate of saturation magnetization is changed from 92% to N
In case of i, it is suppressed to 57%, and in other cases, it is suppressed to 23%. On the other hand, in the magnetic recording film manufactured by using the ion implantation method of the present invention, curve 7 is the case of using TbFeCoNi and curve 8 is the case of TbFeCoX (X = Ti, Ta, Nb), The change rates of the saturation magnetization were 15% and 5%, respectively, which were remarkably suppressed as compared with the conventional method.

(Example 3) A magneto-optical disk was manufactured in the same manner as in Example 1. That is, Tb ₂₈ Fe was formed on the washed circular disk substrate.
A 0.1 μm magnetic recording film having a composition of ₅₉ Co ₈ X (X = Rh, Pt, Pd) was formed by the sputtering method. The sputtering conditions at this time are the same as in Example 1. Subsequently, P, C and B were implanted on this magnetic recording film by the ion implantation method. The energy was controlled so that the driving depth at this time was 100Å. The characteristics of the magneto-optical disk thus manufactured were θ _k = 0.30 °, Hc = 5.0 kOe, and Tc = 180 ° C. Also, when the operation characteristics of this magneto-optical disk were measured, it was C / N = 50 dB. The characteristics of these magneto-optical discs were no different from the case of using the magnetic recording film produced without using the method of the present invention.

After measuring the magnetic characteristics, a life test of this disk was conducted in the same manner as in Example 1, and the results are shown in FIG. In the figure, the horizontal axis represents storage time (hours) and the vertical axis represents saturation magnetization.
The change rate (%) of Ms is shown as a relative value when the initial value is 100. First, a curve 9 shows a change in the saturation magnetization Ms in the case of a magnetic recording film produced without using the ion implantation method of the present invention. In the conventional method, in order to improve corrosion resistance, Rh,
The change of saturation magnetization when Pt and Pd are added is 80 ℃, 95%
When stored in RH for 500 hours, it increased by 1.95 times the initial value. On the other hand, in the magnetic recording film prepared by the ion implantation method, as shown by the curve 10, it increased 1.10 times after 500 hours. Thus, it was found that the magnetic recording film of the present invention can remarkably suppress the change in saturation magnetization.

Example 4 The magneto-optical disk was manufactured by the same method as in Example 1. Ie, on a cleaned circular disc substrate
A 0.1 μm thick magnetic recording film having a composition of Tb ₂₈ Fe ₅₉ Co ₈ X (X = Zr, Al, Ti, Ta) was formed by the sputtering method. The sputtering conditions at this time are the same as in Example 1.
Subsequently, P, P,
B and C were injected. The energy was controlled so that the driving depth at this time was 150Å. Then, surface treatment was performed for 10 minutes in heated N ₂ or O ₂ or O ₂ / Ar = 30/70. The magnetic characteristics of the magneto-optical disk manufactured in this way were measured. As a result, θ _k = 0.30 °, Hc = 5.0 kOe, Tc = 19
It was 0 ° C. Moreover, when the operation characteristics of this magneto-optical disk were measured, it was C / N = 48 dB. In the characteristics of these magneto-optical disks, no difference was observed due to the difference in manufacturing method.

After measuring the magnetic characteristics, a disk life test was performed in the same manner as in Example 1, and the results are shown in FIG.
In the figure, the horizontal axis shows the storage time (hours), and the vertical axis shows the change rate (%) of the saturation magnetization Ms as a relative value when the initial value is 100. First, curves 11 and 12 show changes in the saturation magnetization Ms in the case of a magnetic recording film produced without using the ion implantation method of the present invention. TbFe produced using conventional methods
The change in the saturation magnetization of CoX (X = Zr, Al) was 1.4 times as shown in the curve 11 after standing for 500 hours. Further, in the case of TbFeCoX (X = Ti, Ta) produced in the same manner, the value was 1.2 times as shown by the curve 12. On the other hand, curves 13 and 14 show changes in the saturation magnetization of the magnetic recording film produced by using the ion implantation method of the present invention. The curve 13 is TbFeCoX (X = Z
The change in Ms of the r, Al) film, and the curve 14 shows that TbFeCoX (X
= Ti, Ta) change of Ms of the film is 15% and 5%, respectively, which shows that the change of the saturation magnetization can be remarkably suppressed by using the present invention.

Example 5 A magneto-optical disk was manufactured by the procedure described below. A magnetic recording film having a composition of Tb ₂₈ Fe ₆₄ Co ₈ or Tb ₂₂ Fe ₆₈ Co ₁₀ was formed on the cleaned circular disk substrate made of glass or resin to a film thickness of 0.1 μm by a sputtering method. The conditions at this time were such that Ar was used as the discharge gas, the discharge gas pressure was 5 × 10 ⁻³ Torr, the input RF power density was 1.1 W / cm ² , and the sputtering time was 5 minutes. The substrate was water-cooled during the sputtering. N was formed on the magnetic recording film by the ion implantation method.
I, Cr, Mo, W, Nb or Zr and oxygen were implanted. The driving depth at this time was 150Å. The characteristics of the magneto-optical disk manufactured in this way are that the Kerr rotation angle θ _k is 0.35 to
The holding power Hc was 0.38 ° C., the Curie temperature Tc was 200 ° C., and the holding power Hc was 5.0 kOe. The operating characteristics of this magneto-optical disk were measured and found to be C / N (carrier to noise ratio) = 50 to 53 dB (laser output 7 mW, external magnetic field 200 Oe). These characteristics did not show any difference from the case of TbFeCo alone which did not use the present invention.

Next, a life test of this magneto-optical disk was conducted. The evaluation of the life of the disc is at a temperature of 80 ° C and the relative humidity (RH)
It was performed by measuring the change with time of the saturation magnetization when the prepared disk was stored in a high temperature and high humidity environment of 95%. The result is shown in FIG. In the figure, the horizontal axis indicates the storage time (hours) of the disk in a high temperature and high humidity environment.
The vertical axis shows the change rate (%) of the saturation magnetization Ms as a relative value when the initial value is 100. First, in the case of only TbFeCo, the change of the saturation magnetization increased with the passage of time as shown by the curve 15, and after 500 hours, the initial value increased by 90%. On the other hand, the change in saturation magnetization of the TbFeCo film produced by ion-implanting Mo, W, or Zr and oxygen increased by 25% after 500 hours as shown by the curve 16. The change in saturation magnetization of the magnetic recording film produced by ion implantation of Cr or Nb and oxygen is 50 as shown in the curve 17.
There was only a 6% increase after 0 hours.

From the above results, the corrosion resistance of the magnetic recording film of the magneto-optical disk produced by the method of the present invention can be significantly improved as compared with the film produced by the conventional method,
It can be seen that the present invention is effective in improving the corrosion resistance without deteriorating the magnetic and magneto-optical characteristics.

(Example 6) A method for manufacturing a magneto-optical disk is the same as in Example 5. That is, a magnetic recording film having a composition of Tb ₂₈ Fe ₆₄ Co ₈ or Tb ₂₂ Fe ₆₈ Co ₁₀ of 0.1 μm is formed on a circular disk substrate.
The film thickness was formed by sputtering. The sputtering conditions at this time are the same as in Example 5. Then, Ti, Ta, or Al and nitrogen were implanted into the magnetic recording film by the ion implantation method. The driving depth at this time was controlled to 150Å. The characteristics of the magneto-optical disk manufactured in this way are θ _k = 0.35
The angle was 0.38 °, Hc = 5.0 kOe, and Tc = 200 ° C. Moreover, when the operating characteristics of this disk were measured, C / N = 5
It was 0 to 53 dB. These characteristics were no different from those of the TbFeCo film produced without using the present invention.

Next, the life test of the produced disk was performed. The test method is the same as in Example 5, and the test is shown in FIG. 80 ° C
In the case of the TbFeCo film prepared without using the present invention (curve 15), the change rate (%) of the saturation magnetization when stored in an environment of 95% RH for 500 hours was increased by about 90%. On the other hand, when a TbFeCo film produced by the method of the present invention is implanted with Al and nitrogen (curve 18), the increase is about 20%, and when Ti or Ta and nitrogen are implanted (curve 19). There was no difference between the two and the increase was 8%, and the rate of change in saturation magnetization was extremely small.

From the above results, by using the method of the present invention,
It was possible to significantly improve the corrosion resistance of the magnetic recording film without deteriorating the magnetic and magneto-optical properties.

(Example 7) A method for manufacturing a magneto-optical disk is the same as that in Example 5. That is, Tb ₂₈ Fe ₅₉ Co ₈ X ₅ (X
= Ti, Ta, Nb, Al, Zr, or Ni) was formed by a sputtering method to a film thickness of 0.1 μm. The sputtering conditions at this time are the same as in Example 5. Then, nitrogen or oxygen was implanted into the magnetic recording film by the ion implantation method. The driving depth at this time was 250Å.
The characteristics of the magneto-optical disk manufactured in this way are θ _k
= 0.32 ° ~ 0.35 °, Hc = 3.0kOe, Tc were obtained.

(Embodiment 8) A method for manufacturing a magneto-optical disk is the same as that in Embodiment 5.
That is, Tb ₂₈ Fe ₅₉ Co ₈ X ₅ (X
= Ti, Ta, Nb, Al, Zr, or Ni), a magnetic recording film having a composition of 0.1 μm was formed by a sputtering method. The sputtering conditions at this time are the same as in Example 5. Next, 1 atmosphere of O ₂ , N ₂ or O ₂ / Ar =
In 40/60, the surface of the magnetic recording film was oxidized or nitrided by flowing it at a flow rate of 100 ml / min for about 1 hour. The characteristics of the magneto-optical disk manufactured in this way are θ _k = 0.32 ° to 0.
The temperature was 35 °, Hc = 3.0 kOe, and Tc = 180 ° C. Moreover, when the operating characteristics of this disk were characterized, it was C / N = 49 dB. These characteristics did not differ from those of the magnetic recording film produced without using the method of the present invention.

Next, a life test of the disk was conducted under the same method and conditions as in Example 5. The results are shown in FIG. 80
Saturation magnetization M when stored for 500 hours in an environment of ℃ and 95% RH
The change rate (%) of s is TbFeC produced without using the present invention.
For the oX (X = Al, Zr or Ni) film there was a 40% increase as shown in curve 20. On the other hand, according to the present invention, the magnetic recording film surface-treated with oxygen or nitrogen is 12% as shown by the curve 24.
Increased and decreased significantly. In addition, TbFeCoX (X = Ti, T
In the case of the a, Nb) films, as shown by the curves 21 and 25, there was a large decrease from 15% increase to 5%.

As described above, by using the method of the present invention, the corrosion resistance of the magnetic recording film could be significantly improved without deteriorating the magnetic and magneto-optical characteristics.

Example 9 FIG. 9 shows a schematic diagram of a cross-sectional structure of the manufactured magneto-optical disk as an example of the present invention. The manufacture of magneto-optical disk
The in-line CVR-vacuum deposition-sputtering device was used. That is, first, on the cleaned disk substrate 26, 1% of SiH ₄ , 5% of NH ₃ and the rest of Ar were used as a source gas, laser excitation was performed at a reaction tube internal pressure of 5 Torr, a substrate temperature of 80 ° C. and a reaction time of 2 minutes. The car-enhancement film 27 was formed by the chemical vapor deposition method (L-CVD method). The film thickness was 1200Å. Then, (Gd _0.6 Tb
A magnetic recording film 28 having a composition of _0.4 ) _0.22 (Fe _0.9 Co _0.1 ) _0.78 was formed. The sputtering conditions at this time were Ar discharge gas, sputtering gas pressure 5 × 10 ^-3 Torr, input RF output.
1 W / cm ² , sputtering time 4 minutes, film thickness 1000 Å. Then, subsequently, the protective film 29 was formed by the L-CVD method. The CVD conditions at that time are the same as those in the case of forming the car enhance film 27.

The characteristics of the magneto-optical disk manufactured in this way were that the Kerr rotation angle θ _k was 0.85 degrees, the coercive force Hc was 5.0 kOe, the Curie temperature Tc was 200 ° C., and the C / N (carrier to noise ratio) was 54 dB. . The production of this disc was repeated 10 times,
It was found that the variation in each magneto-optical property was ± 2%, which was significantly smaller than ± 7% when the film was formed by the conventional all-sputtering method. In addition, the density of film defects such as pinholes was measured and found to be 1 × 10 ² pieces / cm ² for a film with a thickness of 1000 Å formed by the L-CVD method and 1 × 10 ² when formed by the sputtering method. ^The defect density could be significantly reduced as compared with ⁴ defects / cm ² . Also, since the film formation by the L-CVD method is a low-temperature film formation, the internal stress is as small as about 1/10 as compared with the conventional sputtering method or the vacuum evaporation method, and the adhesiveness is not peeled off by the tape test. It was found that the L-CVD method did not exist at all, whereas the conventional method caused some peeling, and the adhesiveness was remarkably improved.

By using the L-CVD method as described above, stable film formation can be performed, the number of film defects is small, the internal stress is reduced, the adhesiveness with the underlying layer is improved, and the film formation speed is improved as compared with the conventional method. I found out that I did.

Example 10 The structure of the manufactured magneto-optical disk is as shown in FIG. 9, and is the same as Example 9 except that SiO is used for the car enhance film 27 and the protective film 29. The SiO film is formed by using SiH ₄ 1%, H ₂ 4%, O ₂ 1%, the balance of He or SiH as the source gas.
_{4 1%, N 2 O1%} , using He balance, the reaction tube pressure 3 Torr, a substrate temperature of 80 ° C., was performed by L-CVD method at a reaction time of 2 minutes. The film pressure of the formed SiO film is 120 for the car enhance film 27.
The protective film 29 was 0Å and 1500Å.

The characteristics of the magneto-optical disk manufactured in this way are θ
_{It was k} = 0.90 °, Hc = 5.0 kOe, Tc = 200 ° C., and C / N = 55 dB. This disc was repeatedly manufactured, but the variation in characteristics was ± 3%, which was significantly smaller than the variation of ± 8% of the disc produced by the conventional method. Further, the internal stress and the adhesiveness with the underlying layer were the same as in Example 9.

Example 11 The structure of the manufactured magneto-optical disk is as shown in FIG. 9, and is the same as that of Example 9 except that Si ₃ N ₄ is used for the car enhance film 27 and SiO ₂ is used for the protective film 29. . The conditions for forming the Si ₃ N ₄ film are the same as in Example 9. The SiO ₂ film is formed by using SiH ₄ 1%, O ₂ 2%, and the balance of Ar as the source gas and the reaction pressure.
It was performed by the L-CVD method at 5 Torr, a substrate temperature of 80 ° C., and a reaction time of 2 minutes. The thickness of each layer is 1200 for Car Enhance film 27.
Å, and the protective film 29 is 1500Å.

The characteristics of the magneto-optical disk manufactured in this way are θ
_{It was k} = 0.85 °, Hc = 5 kOe, Tc = 200 ° C., and C / N = 54 dB. The disc characteristic reproducibility, internal stress, and adhesiveness are shown in Example 9.
The same result was obtained.

Example 12 The structure of the manufactured magneto-optical disk is as shown in FIG. 9, and was performed in the same manner as in Example 9 except that TiO ₂ was used for the car enhance film 27 and the protective film 29. For forming the TiO ₂ film, TiCl ₄ 1%, H ₂ O 1% and the balance of Ar were used as a source gas. Here, since TiCl ₄ and H ₂ O are liquids at room temperature,
By bubbling Ar into TiCl ₄ and H ₂ O, TiCl ₄ and H
Included ₂ O. The concentration was adjusted by changing the temperature of TiCl ₄ or H ₂ O and changing the vapor pressure. L-CV
Conditions D are pressure Torr, substrate temperature 90 ° C., and reaction time 2 minutes.

The characteristics of the magneto-optical disk manufactured in this way are θ
_{It was k} = 0.80 °, Hc = 5.0 kOe, Tc = 200 ° C., and C / N = 53 dB. Here, the film thickness of the car enhance film 27 is 1200Å, and the film thickness of the protective film 29 is 1500Å. The reproducibility of the disc characteristics, the internal stress, and the adhesiveness due to the repeated production were almost the same as the results in Example 9.

Example 13 The structure of the manufactured magneto-optical disk is as shown in FIG. 9, and is the same as that of the example except that TiN is used for the car enhance film 27 and the protective film 29. For forming the TiN film, TiCl ₄ %, NH ₃ 5% and the balance of Ar were used as a source gas. The TiCl ₄ concentration was adjusted by the same method as in Example 12. The L-CVD conditions are the same as in Example 12 such as pressure Torr, substrate temperature 90 ° C., and reaction time 2 minutes.

The characteristics of the magneto-optical disk manufactured in this way are θ
_{It was k} = 0.87 °, Hc = 5 kOe, Tc = 200 ° C., and C / N = 54 dB. Here, the thickness of each layer is 1,200 for the car enhance film 27.
Å, the protective film 29 is 1500Å. The reproducibility of the disc characteristics, the internal stress, and the adhesiveness due to the repeated fabrication were the same as the effects in Example 9.

〔The invention's effect〕

As described in detail above, a magnetic recording film having a passivation layer formed by ion-implanting a passivation element and an oxidation-promoting element into the surface portion of the magnetic recording film constituting the magneto-optical disk of the present invention, or A magnetic recording film on which a stable oxide or nitride protective film is formed by ion-implanting oxygen, nitrogen or a mixed gas thereof or by performing a surface treatment in the above gas atmosphere is a magnetic recording film Since the corrosion resistance can be remarkably improved without deteriorating the magneto-optical characteristics, a magneto-optical disk having excellent performance with high durability and reliability can be obtained. Further, in this case, since it is not necessary to form another protective film on the magnetic recording film, the structure of the magneto-optical disk can be simplified and the manufacturing process can be simplified.

In the formation of various films constituting the magneto-optical disk, by using the L-CVD method of the present invention, it is possible to form a film at a low temperature, so that the internal stress of the film can be reduced and the film has high energy. Since the particles do not collide with the substrate or the underlayer, the substrate or the underlayer is not destroyed and damaged, and the adhesive force with the substrate or the underlayer is higher than that of the conventional method regardless of film formation at low temperature. Large, the source gas is supplied with sufficiently large excitation energy by the laser beam, the film formation rate is high, the controllability and uniformity of the reaction are excellent, and the reproducibility of the film formation is significantly improved. Reliable magneto-optical disk with good quality of magnetic and magneto-optical properties, good corrosion resistance and durability with few high quality car enhance film, protective film, etc. It can be produced.

[Brief description of drawings]

FIG. 1 is a graph showing the time-dependent changes in saturation magnetization and Kerr rotation angle of the magnetic recording film of Example 1 of the present invention, and FIG. 2 is a graph showing the time-dependent change in saturation magnetization of the magnetic recording film of Example 2. FIG. 3 is a graph showing the change rate of the saturation magnetization of the magnetic recording film of Example 3 with time. FIG. 4 is a graph showing the change rate of the saturation magnetization of the magnetic recording film of Example 4 with time. A graph showing the change rate of the saturation magnetization of the magnetic recording film of Example 5 with time,
FIG. 6 is a graph showing the change over time of the saturation magnetization of the magnetic recording film of Example 6, FIG. 7 is a graph showing the change over time of the saturation magnetization of the magnetic recording film of Example 7, and FIG. FIG. 9 is a graph showing the change over time in the saturation magnetization of the magnetic recording film, and FIG. 9 is a schematic diagram showing the structure of the magneto-optical disk produced in Examples 9 to 13. 1 ...... TbFeCo film Ms change 2 ...... TbFeCo film theta _k changes 3 ...... Implanted TbFeCo film Ms change 4 ...... Implanted theta _k changes in TbFeCo film 5 ...... TbFeCoNi film 6 ...... TbFeCoX ( X = Ti, Ta, Nb) film 7 ... Ion-implanted TbFeCoNi film 8 ... Ion-implanted TbFeCoX (X = Ti, Ta, Nb) film 9 ... TbFeCoX (X = Pd, Rh, Pt) film 10 ... … Ion-implanted TbFeCoX (X = Pd, Rh, Pt) film 11 …… TbFeCoX (X = Zr, Al) film 12 …… TbFeCoX (X = Ti, Ta) film 13 …… Ion-implanted TbFeCoX (X = Zr) , Al) film 14 ... Ion-implanted TbFeCoX (X = Ti, Ta) film 15 ... TbFeCo film 16 ... TbFeCo ion-implanted with Mo, W or Zr and oxygen
Film 17 ... TbFeCo film in which Cr or Nb and oxygen are ion-implanted 18 ... TbFeCo film in which Al and nitrogen are ion-implanted 19 ... TbFeCo film 20 ... TbFeCoX (X = Al, Zr or Ni) film 21 ... TbFeCoX (X = Ti, Ta or Nb) film 22 ... TbFeCoX (X = A) implanted with oxygen or nitrogen ions
L, Zr or Ni) film 23 ... TbFeCoX (X = T) implanted with oxygen or nitrogen ions
i, Ta or Nb) film 24 ... TbFeCoX (X = A) surface-treated with oxygen or nitrogen
l, Zr or Ni) film 25 ... TbFeCoX (X = T) surface-treated with oxygen or nitrogen
i, Ta or Nb) film 26 ... Substrate, 27 ... Car enhance film 28 ... Magnetic recording film, 29 ... Protective film

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshio Suzuki 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-60-163248 (JP, A) JP-A-60 -17078 (JP, A) JP 62-200552 (JP, A) JP 62-175946 (JP, A)

Claims (4)

(57) [Claims] Claims: 1. An alloy of a rare earth element and an iron group element, or an alloy of a rare earth element and an iron group element is used for Ti, Ta, Nb, Al, Zr,
A magneto-optical disk having a magnetic recording film made of an alloy containing 10 atomic% or less of at least one element selected from the group consisting of Ni, Pt, Rh, and Pd, and promoting passivation or oxidation in the magnetic recording film. At least one element selected from the group of P, As, and Se, which is an element for improving corrosion resistance, and at least one element selected from the group of C, B, Si, Ge, He, Ne, and H, or P, As , At least one element selected from the group of Se, and at least one element selected from the group of C, B, Si, Ge, He, Ne, H and selected from the group of Mo, W, Cr, Re, Ru Characterized in that it has a corrosion-resistant protective layer formed by ion-implanting at least one element selected from the group consisting of oxygen and nitrogen, or at least one element selected from oxygen and nitrogen, to a depth of 1/2 or less of the thickness of the magnetic recording film. A magneto-optical disk. 2. A magnetic recording film made of an alloy of a rare earth element and an iron group element, a gas containing at least one element selected from oxygen and nitrogen, and Ti, Ta, Nb, Al, Zr, N.
Corrosion resistant protective layer formed by simultaneously ion-implanting at least one metal element selected from the group of i, Cr, Mo and W, or after ion-implanting the metal element, ion-implanting the gas into the magnetic recording film. A magneto-optical disk having a corrosion-resistant protective layer formed as described above. 3. The magneto-optical disk according to claim 1 or 2, wherein the ion implantation amount of the element to be ion-implanted into the magnetic recording film is 1 × 10 ^{16 to} 3 × 10 ¹⁷ pieces / cm 3. ^A magneto-optical disk characterized by a range of ² . 4. An alloy of a rare earth element and an iron group element, or an alloy of a rare earth element and an iron group element for Ti, Ta, Nb, Al, Zr,
A method for manufacturing a magneto-optical disk having a magnetic recording film made of an alloy containing 10 atomic% or less of at least one element selected from the group consisting of Ni, Pt, Rh, and Pd, wherein the magnetic recording film is passivated. At least one element selected from the group of P, As and Se, which is a corrosion resistance improving element that promotes oxidation or oxidation, and at least one element selected from the group of C, B, Si, Ge, He, Ne and H , Or at least one element selected from the group of P, As, Se and at least one element selected from the group of C, B, Si, Ge, He, Ne, H, and Mo, W, Cr, Re, At least one element selected from the group consisting of Ru and at least one element selected from oxygen and nitrogen is formed before or after ion implantation of at least one element selected from the group of Ru to a depth of 1/2 or less of the film thickness of the magnetic recording film. Specially including at least a step of heat treatment in a gas containing an element. Preparation of the magneto-optical disk to.