JP2810573B2 - Manufacturing method of magneto-optical element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magneto-optical element for recording, erasing and reproducing information by using light such as laser light.

[0002]

2. Description of the Related Art A Co / Pt multilayer film in which a Pt layer and a Co layer are alternately and repeatedly laminated not only has a perpendicular magnetic anisotropy but also has a larger size than a rare earth transition metal alloy with respect to short wavelength light. It has a car rotation angle. For this reason, a magneto-optical element using a Co / Pt multilayer film has attracted attention as a magneto-optical recording medium capable of high-density magneto-optical recording. In order to stably retain recorded information, it is desired that the Co / Pt multilayer film has a high coercive force. On page 55 of the Abstracts of the Japanese Society of Applied Magnetics, published in 1989,
It has been reported that when an o / Pt multilayer film is formed by a sputtering method, a Co / Pt multilayer film having a high coercive force can be obtained by increasing the pressure of Ar gas as a sputtering gas. Also, on page 56 of the summary, it is found that a Co / Pt multilayer film having a high coercive force can be obtained by forming a Co / Pt multilayer film on a metal film having an fcc lattice such as Pt or Pd by a sputtering method. It has been reported.

[0003]

However, when a Co / Pt multilayer film is formed under a high Ar gas pressure, the Co / Pt multilayer film contains many holes. Also, C on the metal film
When an o / Pt multilayer film is formed, a four-layer structure of a dielectric layer / recording layer / dielectric layer / reflection film cannot be adopted, and an effective increase in the Kerr rotation angle cannot be achieved. Co /
The increase in vacancies in the Pt multilayer film causes noise at the time of information reproduction, and the fact that a 4-layer structure cannot be employed to effectively increase the Kerr rotation angle means that a large signal intensity cannot be obtained at the time of information reproduction. Have a point.

[0004]

According to a method of manufacturing a magneto-optical storage element of the present invention, a method for manufacturing a magneto-optical storage element comprising the steps of:
After a crystalline MgO film is formed on the metal film by sputtering an O target under a mixed gas of O ₂ gas and Ar gas, a Pt target and a Co target are alternately sputtered under an inert gas. The Mg
In the method for manufacturing a magneto-optical element in which a Co / Pt multilayer film in which a Pt layer and a Co layer are alternately stacked on an O film is formed, a high coercive force Co / Pt multilayer film is obtained when the MgO film is formed. It is characterized in that the partial pressure of O ₂ gas is set.

[0005]

According to the above-mentioned structure, the partial pressure of the O ₂ gas is set so that a Co / Pt multilayer film having a high coercive force can be obtained when the MgO film is formed.
A Co / Pt multilayer film having a high coercive force can be obtained without manufacturing a t multilayer film. Also, since a Co / Pt multilayer film is formed on the transparent crystal, the dielectric layer / recording layer / dielectric layer / reflection layer
A layer structure can be obtained, and a large signal intensity can be obtained. In this case, the reflection film is a metal layer containing at least one element of Pt, Pd, Ag, and Al.

[0006]

FIG. 3 shows a magneto-optical storage element manufactured in this embodiment.
Shown in In FIG. 3, 1 is a substrate made of a resin such as glass or polycarbonate, 2 is a reflection film made of a Pt layer formed on the substrate 1, 3 is an MgO layer formed on the Pt layer, and 4 is Co / Pt. The multilayer film 5 is an amorphous AlN film. The Co / Pt multilayer film 4 has a configuration in which Pt layers 6 and Co layers 7 are alternately stacked.

The Pt layer 2 and the Co / Pt multilayer film 4 were formed by sputtering a Pt target and a Co target using Ar gas. For the MgO layer, set the MgO target to A
A film was formed by sputtering under a mixed gas of r and O ₂ . Al
The N layer was produced by sputtering an Al target under a mixed gas of N ₂ and Ar. The Pt layer 2 is 500 angstroms, the MgO layer 3 is 400 angstroms, Co / P
The t multilayer film layer has a Pt layer 6 of 16.5 angstroms, C
Ten sets of layers each having 3.5 Å of the o layer 7 were alternately laminated. The AlN layer is 300 Å.

In the device having the structure as shown in FIG.
When producing the O film, the partial pressure of the O ₂ gas is changed to form a film,
The result of examining the relationship between the coercive force (Hc) of the obtained Co / Pt multilayer film and the conditions for forming the MgO layer is curve 8 in FIG. However, the total pressure of the mixed gas of Ar and O ₂ is 5 mTo
rr. As shown in FIG. 1, the coercive force of the Co / Pt layer largely depends on the partial pressure of O ₂ gas during the formation of MgO, and the partial pressure of O _{2 is} set to an appropriate value (2 × 10 ⁻⁵ Torr in this embodiment). It turned out that the coercive force was maximized.

Next, the MgO film 3 of the above magneto-optical storage element
Was examined by X-ray diffraction. FIG. 2 shows the MgO (11
1) The position of the diffraction peak due to the plane is indicated by an arrow, and the X-ray diffraction pattern of the MgO film produced at each O ₂ partial pressure is shown. This indicates that when the O ₂ partial pressure takes an appropriate value, the diffraction peak from the (111) plane of the MgO film increases.

Considering the results of FIGS. 1 and 2, Mg
It is considered that the (111) orientation of the O film greatly affects the Hc of the Co / Pt layer. As described above, Mg
By setting an appropriate O ₂ partial pressure during the formation of the O film, Co /
The coercive force of the Pt layer can be increased. Therefore Co
It is not necessary to increase the Ar gas pressure during the formation of the / Pt layer, so that a Co / Pt layer having few vacancies can be manufactured. Note that Ar
The conventional method requires a gas pressure of 30 mTorr, whereas the method of the present invention requires a gas pressure of 5 mTorr and a small porosity of Co.
/ Pt film can be manufactured. Since the MgO film is a transparent film, the Kerr rotation angle can be efficiently enhanced.

As described above, according to the method of manufacturing the magneto-optical storage element of the present embodiment, the Co is produced by using a transparent underlayer with few holes.
Since the / Pt multilayer film can be obtained, a magneto-optical memory element having a small noise and a high signal intensity at the time of information reproduction can be manufactured.

[0012]

As described above, the method of manufacturing a magneto-optical memory element according to the present invention has a high coercivity Co / Pt during the formation of an MgO film.
Since the O ₂ partial pressure is set so as to obtain a layer, a high A
A Co / Pt layer having a high coercive force can be obtained without forming a Co / Pt film under the r gas pressure. For this reason, a Co / Pt film with a small number of holes and a high coercive force can be obtained. Further, the transparent film M
Since the Co / Pt layer is formed on the gO layer, the dielectric layer /
A magneto-optical element having a four-layer structure of (Co / Pt layer) / dielectric layer / reflection layer can be manufactured, and the effect of enhancing the Kerr rotation angle can be efficiently obtained. As described above, there is an effect that it is possible to manufacture a magneto-optical element having a small noise and a high signal strength during information reproduction.

[Brief description of the drawings]

FIG. 1 shows the dependency of the coercive force of a Co / Pt multilayer film among the films of the present invention on the partial pressure of O ₂ when an MgO layer is formed.

[Figure 2] in the construction of membranes of the present invention, an X-ray diffraction patterns of different samples of O ₂ partial pressure during the MgO layer prepared.

FIG. 3 is a sectional view of a magneto-optical element according to the present invention.

[Description of Signs] 1 Substrate 2 Pt layer 3 MgO layer 4 Co / Pt multilayer film 6 Pt layer in Co / Pt multilayer film 7 Co layer in Co / Pt multilayer film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-56752 (JP, A) JP-A-2-69907 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 11/10 541 H01F 41/18

Claims (1)

(57) [Claims] 1. A single or alloy layer containing at least one element of Pt, Pd, Ag, and Al is formed on a substrate, and an MgO target is formed thereon by using a mixed gas of O ₂ gas and Ar gas. Crystalline Mg by sputtering with
After forming the O layer, a Pt target and a Co target are alternately sputtered under an inert gas to alternately laminate a Pt layer and a Co layer on the MgO layer.
In a method for manufacturing a magneto-optical element for forming a multilayer film,
A method of manufacturing a magneto-optical element, wherein the partial pressure of the O ₂ gas is set so that a Co / Pt multilayer film having a high coercive force is obtained when the MgO layer is formed.