JPH0419618B2 - - Google Patents
Info
- Publication number
- JPH0419618B2 JPH0419618B2 JP13943484A JP13943484A JPH0419618B2 JP H0419618 B2 JPH0419618 B2 JP H0419618B2 JP 13943484 A JP13943484 A JP 13943484A JP 13943484 A JP13943484 A JP 13943484A JP H0419618 B2 JPH0419618 B2 JP H0419618B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- transparent dielectric
- dielectric film
- magneto
- alloy thin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000010408 film Substances 0.000 claims description 106
- 239000010409 thin film Substances 0.000 claims description 26
- 229910045601 alloy Inorganic materials 0.000 claims description 24
- 239000000956 alloy Substances 0.000 claims description 24
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 22
- -1 rare earth transition metal Chemical class 0.000 claims description 22
- 229910052723 transition metal Inorganic materials 0.000 claims description 22
- 150000004767 nitrides Chemical class 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 4
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical group Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical group N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 12
- 239000007789 gas Substances 0.000 description 6
- 238000004544 sputter deposition Methods 0.000 description 5
- 229910004298 SiO 2 Inorganic materials 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 230000005374 Kerr effect Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 239000002131 composite material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000005546 reactive sputtering Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F10/00—Thin magnetic films, e.g. of one-domain structure
- H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
- H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
- H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
- H01F10/14—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing iron or nickel
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10582—Record carriers characterised by the selection of the material or by the structure or form
- G11B11/10586—Record carriers characterised by the selection of the material or by the structure or form characterised by the selection of the material
- G11B11/10589—Details
- G11B11/10593—Details for improving read-out properties, e.g. polarisation of light
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F10/00—Thin magnetic films, e.g. of one-domain structure
- H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
- H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
- H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
- H01F10/126—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing rare earth metals
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
Description
【発明の詳細な説明】
＜発明の技術分野＞
本発明はレーザ等の光を照射することにより情
報の記録・再生・消去等を行なう磁気光学記憶素
子に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Technical Field of the Invention> The present invention relates to a magneto-optical storage element that records, reproduces, erases, etc. information by irradiating it with light such as a laser.
＜発明の技術的背景とその問題点＞
近年、情報の書換えが可能な光デイスクとして
磁気光学記憶素子の研究が活発に行なわれてい
る。中でも記憶媒体として希土類遷移金属非晶質
合金薄膜を用いて構成したものは、記録ビツトが
粒界の影響を受けない点及び記録媒体の膜を大面
積に亘つて作成することが比較的容易である点か
ら特に注目を集めている。<Technical background of the invention and its problems> In recent years, research has been actively conducted on magneto-optical storage elements as optical disks on which information can be rewritten. Among these, those constructed using rare earth transition metal amorphous alloy thin films as storage media have the advantage that recording bits are not affected by grain boundaries and that it is relatively easy to create a recording medium film over a large area. It has attracted particular attention for one reason.
しかし上記記録媒体として希土類遷移金属非晶
質合金薄膜を用いて磁気光学記憶素子を構成した
ものでは、一般に光磁気効果（カー効果、フアラ
デー効果）が十分得られずその為再生信号のＳ／
Ｎが十分なものであつた。 However, when a magneto-optical storage element is constructed using a rare earth transition metal amorphous alloy thin film as the above-mentioned recording medium, the magneto-optical effect (Kerr effect, Faraday effect) is generally not sufficiently obtained.
N was sufficient.
これに対する対応策として既に本発明者等は次
の如き素子構造の改良を試みた。 As a countermeasure to this problem, the inventors of the present invention have already attempted to improve the device structure as follows.
第３図は既に改良を試みた素子構造の磁気光学
記憶素子の一部側面断面図を示す。 FIG. 3 shows a partial side sectional view of a magneto-optical memory element whose structure has already been improved.
第３図において、１はガラス、ポリカーボネー
ト、アクリル等の透明基板であり、該透明基板１
上に第１の透明誘電体膜である透明なSiO膜２
（膜厚120nｍ）が形成され、該SiO膜２上に希土
類遷移金属膜であるGdTbFe合金薄膜３（膜厚
15nｍ）が形成され、該GdTbFe合金薄膜３上に
第２の透明誘電体膜である透明なSiO2膜４（膜
厚50nｍ）が形成され、該SiO2膜４上に反射膜で
あるCu膜５（膜厚50nｍ）が形成されている。以
上の構造では見かけのカー回転角が1.75°もの大
きな値が得られた。 In FIG. 3, 1 is a transparent substrate made of glass, polycarbonate, acrylic, etc.
A transparent SiO film 2 which is a first transparent dielectric film is placed on top.
(film thickness: 120 nm) is formed on the SiO film 2, and a GdTbFe alloy thin film 3 (film thickness:
A transparent SiO 2 film 4 (film thickness 50 nm), which is a second transparent dielectric film, is formed on the GdTbFe alloy thin film 3, and a Cu film, which is a reflective film, is formed on the SiO 2 film 4. 5 (film thickness 50 nm) is formed. In the above structure, the apparent Kerr rotation angle was as large as 1.75°.
以上の素子構造の採用によつてカー回転角が著
しく大きなものを得ることのできた理由を次に説
明する。 The reason why it was possible to obtain a significantly large Kerr rotation angle by adopting the above element structure will be explained below.
第３図に示す如く透明基板１側からレーザ光６
を希土類遷移金属合金薄膜３に照射した場合、入
射レーザ光が第１透明誘電体膜２の内部で反射が
繰り返され、干渉した結果見かけ上のカー回転角
が増大するものであり、この際上記第１の透明誘
電体膜２の屈折率が大きい程、カー回転角の増大
効果は大きい。 As shown in FIG.
When irradiating the rare earth transition metal alloy thin film 3 with The larger the refractive index of the first transparent dielectric film 2, the greater the effect of increasing the Kerr rotation angle.
又第３図に示す如く希土類遷移金属合金薄膜３
の背面に反射膜１５を配置したことで見かけ上の
カー回転角を増大させており、希土類遷移金属合
金薄膜３と反射膜５の間に第２の透明誘電体膜４
を介在させることで見かけ上のカー回転角を更に
増大させている。 Moreover, as shown in FIG. 3, a rare earth transition metal alloy thin film 3
The apparent Kerr rotation angle is increased by disposing the reflective film 15 on the back surface of the second transparent dielectric film 4 between the rare earth transition metal alloy thin film 3 and the reflective film 5.
By interposing this, the apparent Kerr rotation angle is further increased.
次にこの作用の原理について定性的に説明を行
なう。 Next, the principle of this action will be qualitatively explained.
上記第２の透明誘電体膜４と反射膜５との複合
膜を一つの反射層Ａとして考える。第３図に於
て、透明基板１側から入射し、希土類遷移金属合
金薄膜３を通過し、上記反射層Ａにて反射された
後上記希土類遷移金属合金薄膜３を再び通過した
光と、透明基板１側から入射し希土類遷移金属合
金薄膜３の表面で反射された光とが合成される
が、この場合入射光が希土類遷移金属合金薄膜３
の表面で反射することにより生起されるカー効果
と、入射光が希土類遷移金属合金薄膜３の内部を
通過することにより生起されるフアラデー効果と
が合わされることにより、見かけ上のカー回転角
が増大するものである。上記構造の磁気光学記憶
素子に於ては上記フアラデー効果を如何にしてカ
ー効果に加えるかが極めて重要になる。フアラデ
ー効果について謂えば記録媒体の層厚を厚くすれ
ば回転角を大きくできるが、入射レーザ光が記録
媒体に吸収される為、所期の目的を達成し得な
い。よつて上記記録媒体の適切な層厚の値は概ね
10〜50nｍであり、その値は使用するレーザ光の
波長や上記反射層の屈折率等により決定される。
上記反射層に対して求められる条件は上記の説明
から判るように反射率が高いことにある。言い替
えると入射レーザ光を反射層内に入れないことで
あり、光学的に見れば反射層（第２の透明誘電体
膜＋反射膜）の等価的な屈折率が０に近いことが
必要である。この為には第２の透明誘電体膜の実
数部の値が小さく且つ虚数部の値が０で、更に反
射膜の実数部の値が小さいことが必要である。 A composite film of the second transparent dielectric film 4 and the reflective film 5 will be considered as one reflective layer A. In FIG. 3, light that is incident from the transparent substrate 1 side, passes through the rare earth transition metal alloy thin film 3, is reflected by the reflective layer A, and then passes through the rare earth transition metal alloy thin film 3 again, and the transparent The light incident from the substrate 1 side and reflected on the surface of the rare earth transition metal alloy thin film 3 is combined, but in this case, the incident light is
The apparent Kerr rotation angle increases due to the combination of the Kerr effect caused by reflection on the surface of the rare earth transition metal alloy thin film 3 and the Faraday effect caused by the incident light passing through the inside of the rare earth transition metal alloy thin film 3. It is something to do. In the magneto-optical memory element having the above structure, it is extremely important how to add the Faraday effect to the Kerr effect. Regarding the Faraday effect, the rotation angle can be increased by increasing the layer thickness of the recording medium, but since the incident laser beam is absorbed by the recording medium, the intended purpose cannot be achieved. Therefore, the appropriate layer thickness value for the above recording medium is approximately
It is 10 to 50 nm, and its value is determined by the wavelength of the laser beam used, the refractive index of the reflective layer, etc.
As can be seen from the above description, the condition required for the reflective layer is that it has a high reflectance. In other words, the incident laser beam should not enter the reflective layer, and from an optical perspective, the equivalent refractive index of the reflective layer (second transparent dielectric film + reflective film) must be close to 0. . For this purpose, it is necessary that the value of the real part of the second transparent dielectric film is small and the value of the imaginary part is 0, and furthermore, the value of the real part of the reflective film is small.
以上の如く透明基板１と希土類遷移金属合金薄
膜３との間に介する第１の透明誘電体膜２、及び
希土類遷移金属合金薄膜３の背面の反射層Ａの構
成を付加することによつてカー回転角の増大の効
果を得ることができる。 As described above, by adding the configuration of the first transparent dielectric film 2 interposed between the transparent substrate 1 and the rare earth transition metal alloy thin film 3, and the reflective layer A on the back side of the rare earth transition metal alloy thin film 3, the car The effect of increasing the rotation angle can be obtained.
しかし、上述の効果が得られる反面で、第１の
透明誘電体膜２としてSiO膜を選択し、第２の透
明誘電体膜４としてSiO膜を選択した場合、希土
類遷移金属合金薄膜３が酸化されるという問題が
発生した。本発明者はこの原因が上記SiO膜及び
SiO2膜の中に含有される酸素にあることを確認
した。即ち上記SiO膜及びSiO2膜の成膜時、ある
いは成膜後の内部の酸素成分が分離等して希土類
遷移金属合金薄膜３が酸化されるものである。し
かるに希土類遷移金属合金薄膜３は酸化されるこ
とによつて磁気記録媒体としての能力を著しく阻
害されるものであるから上記酸化の問題は極めて
重大である。又、上記希土類遷移金属合金薄膜３
の膜厚が薄い場合は僅かの酸化であつても影響が
大きいので非常な注意が必要である。 However, while the above effects can be obtained, when an SiO film is selected as the first transparent dielectric film 2 and a SiO film is selected as the second transparent dielectric film 4, the rare earth transition metal alloy thin film 3 is oxidized. A problem arose. The inventor believes that this is due to the above-mentioned SiO film and
It was confirmed that this is due to the oxygen contained in the SiO 2 film. That is, during the formation of the SiO film and the SiO 2 film, or after the film formation, the oxygen component inside is separated, etc., and the rare earth transition metal alloy thin film 3 is oxidized. However, when the rare earth transition metal alloy thin film 3 is oxidized, its ability as a magnetic recording medium is significantly inhibited, so the problem of oxidation is extremely serious. Moreover, the rare earth transition metal alloy thin film 3
If the film is thin, even a small amount of oxidation will have a large effect, so extreme care must be taken.
＜発明の目的＞
本発明は以上の問題点を解消する為になされた
ものであり、磁気光学特性を充分に確保し得ると
共に希土類遷移金属合金薄膜の酸化を防止した新
規な磁気光学記憶素子を提供することを目的とす
るものであり、この目的を達成するために、本発
明は透明基板上に第１の透明誘電体膜、希土類遷
移金属合金薄膜、第２の透明誘電体膜、反射膜を
この順に被覆してなる磁気光学記憶素子におい
て、前記第１の透明誘電体膜及び第２の透明誘電
体膜を、共に同一の材料の窒化物で形成し、且つ
前記第１の透明誘電体膜の屈折率が前記第２の透
明誘電体膜の屈折率より大であるように構成した
ことを特徴とする磁気光学記憶素子である。ま
た、本発明は上記窒化物を窒化アルミニウムとし
たことを特徴とする磁気光学記憶素子である。さ
らに、本発明は上記窒化物を窒化シリコンとした
ことを特徴とする磁気光学記憶素子である。<Purpose of the Invention> The present invention has been made to solve the above problems, and provides a novel magneto-optical memory element that can sufficiently ensure magneto-optical properties and prevents oxidation of a rare earth transition metal alloy thin film. In order to achieve this objective, the present invention provides a first transparent dielectric film, a rare earth transition metal alloy thin film, a second transparent dielectric film, and a reflective film on a transparent substrate. In the magneto-optical memory element, the first transparent dielectric film and the second transparent dielectric film are both formed of nitride of the same material, and the first transparent dielectric film and the second transparent dielectric film are coated in this order. The magneto-optical memory element is characterized in that the refractive index of the film is larger than the refractive index of the second transparent dielectric film. Further, the present invention is a magneto-optical memory element characterized in that the nitride is aluminum nitride. Furthermore, the present invention is a magneto-optical memory element characterized in that the nitride is silicon nitride.
＜発明の実施例＞
以下、図面を参照して本発明の一実施例を詳細
に説明する。<Embodiment of the Invention> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
第１図は本発明に係る磁気光学記憶素子の一実
施例の構成を示す一部側面断面図である。 FIG. 1 is a partial side cross-sectional view showing the structure of an embodiment of a magneto-optical storage element according to the present invention.
同図において、１はガラス、ポリカーボネー
ト、アクリル等の透明基板であり、該透明基板１
上に第１の透明誘電体膜である透明なAlN膜７
（膜厚90nｍ）を形成し、このAlN膜７上に希土
類遷移金属合金薄膜であるGdTbFe合金薄膜３
（膜厚35nｍ）を形成し、このGdTbFe合金薄膜３
上に第２の透明誘電体膜である透明なAlN膜８
（膜厚40nｍ）を形成に、このAlN膜８上に反射
膜であるAlN膜９（膜厚40nｍ以上）を形成して
いる。 In the figure, 1 is a transparent substrate made of glass, polycarbonate, acrylic, etc.
A transparent AlN film 7 which is a first transparent dielectric film is placed on top.
(thickness: 90 nm), and on this AlN film 7, a GdTbFe alloy thin film 3, which is a rare earth transition metal alloy thin film, is formed.
(thickness: 35 nm), and this GdTbFe alloy thin film 3
A transparent AlN film 8 which is a second transparent dielectric film is placed on top.
(film thickness: 40 nm), and on this AlN film 8, an AlN film 9 (film thickness: 40 nm or more), which is a reflective film, is formed.
以上の構造の磁気光学記憶素子に於て、特に注
目すべき点は第１の透明誘電体膜として高い屈折
率を有するAlN膜を用い、第２の透明誘電体膜
として低い屈折率のAlN膜を用いた事である。 What is particularly noteworthy about the magneto-optical memory element having the above structure is that an AlN film with a high refractive index is used as the first transparent dielectric film, and an AlN film with a low refractive index is used as the second transparent dielectric film. This is what was used.
この構造の優利な点について以下説明する。 The advantages of this structure will be explained below.
AlNは高融点の材料であり極めて安定であ
り、又窒化物である為酸化物の膜に比較して緻
密な膜が形成できる。 AlN is a material with a high melting point and is extremely stable, and since it is a nitride, it can form a denser film than an oxide film.
第１の透明誘電体膜であるAlN膜を屈折率
が2.0程度となるように製膜し、一方、第２の
透明誘電体膜であるAlN膜を屈折率が1.9〜1.8
程度となるように製膜することにより、相対的
に第１の透明誘電体膜の屈折率を第２の透明誘
電体膜の屈折率より大きくし、その結果前述し
た如く屈折率の大きい第１の透明誘電体膜によ
つてカー回転角の増大効果が得られ、一方、屈
折率の小さい第２の透明誘電体膜によつて反射
率を高くすることができる。即ち上記屈折率の
異なるAlN膜の組合せは極めて都合が良いこ
とになる。尚、上記構造においてAlN膜７は
90nｍをピークとして±10％程度の膜厚であれ
ば良好であり、又AlN膜８は40nｍをピークと
した±10％程度の膜厚であれば良好である。 The AlN film, which is the first transparent dielectric film, is formed to have a refractive index of approximately 2.0, while the AlN film, which is the second transparent dielectric film, is formed to have a refractive index of 1.9 to 1.8.
By forming the film such that the refractive index of the first transparent dielectric film is relatively higher than that of the second transparent dielectric film, as described above, the refractive index of the first transparent dielectric film is relatively larger than that of the second transparent dielectric film. The effect of increasing the Kerr rotation angle can be obtained by the transparent dielectric film, and on the other hand, the reflectance can be increased by the second transparent dielectric film having a small refractive index. That is, the above combination of AlN films having different refractive indexes is extremely convenient. In addition, in the above structure, the AlN film 7 is
It is good if the film thickness is about ±10% with a peak of 90 nm, and it is good if the AlN film 8 has a thickness of about ±10% with a peak of 40 nm.
上記AlNはその成分として酸素を含有しな
いので希土類遷移金属合金薄膜が酸化される危
険性を極度に減少せしめ得る。 Since AlN does not contain oxygen as a component, the risk of oxidation of the rare earth transition metal alloy thin film can be extremely reduced.
次に同一の窒化物の膜であるAlN膜の屈折率
を異ならせて製膜する方法についてスパツタ法に
よる作製方法を例に挙げて説明する。 Next, a method of forming AlN films, which are films of the same nitride, with different refractive indexes will be described using a method of forming by sputtering as an example.
スパツタリング法によるAlN膜の作製方法に
おいて、ターゲツトには高純度のAlを使用し、
ガスはArとN2の混合ガスを使用し、反応性スパ
ツタによりAlN膜を作製する。 In the sputtering method for producing an AlN film, high-purity Al is used as the target.
A mixed gas of Ar and N 2 is used as the gas, and an AlN film is produced by reactive sputtering.
種々のスパツタ条件で作製したAlNの屈折率
を第２図に示す。この第２図から明らかなように
屈折はArとN2の比較には余り関係せず、ガスの
圧力に依存しており、ガス圧が低い条件で製膜し
た場合には屈折率が大きく、ガス圧が高い条件で
製膜した場合には屈折率が低くなる。したがつて
スパツタ条件により、目的の屈折率を有する透明
誘電体膜を得ることが出来る。 Figure 2 shows the refractive index of AlN produced under various sputtering conditions. As is clear from Figure 2, refraction has little to do with the comparison between Ar and N 2 , but rather depends on the gas pressure, and when the film is formed under low gas pressure, the refractive index is large; When the film is formed under conditions of high gas pressure, the refractive index becomes low. Therefore, depending on the sputtering conditions, a transparent dielectric film having a desired refractive index can be obtained.
なお、上記実施例においては窒化物として
AlNを例にして説明したが、本発明はこれに限
定されるものではなく、例えばSiN膜を用いた場
合にも同様の作用効果を奏するため、第１及び第
２の透明誘電体膜として屈折率の異なるSiN膜を
用いることも可能である。 In addition, in the above example, as a nitride
Although AlN has been described as an example, the present invention is not limited to this. For example, the same effect can be achieved even when using a SiN film, so the refractive index can be used as the first and second transparent dielectric films. It is also possible to use SiN films with different ratios.
上記の如き同一の窒化物における屈折率の相違
は主として作製される膜の密度及びまたは窒素と
他の物質の構成比の相違に起因しているものと推
測される。 It is presumed that the difference in refractive index of the same nitride as described above is mainly due to the difference in the density of the produced film and/or the difference in the composition ratio of nitrogen and other substances.
＜発明の効果＞
以上説明したように、本発明は第１の透明誘電
体膜及び第２の透明誘電体膜を、共に同一の材料
の窒化物で形成し、且つ第１の透明誘電体膜の屈
折率が第２の透明誘電体膜の屈折率より大である
ように構成した、換言すると、屈折率の異なる窒
化膜を組み合わせて構成したので記録媒体の耐蝕
性を確保できると共に、良好な情報再生特性を得
ることができる磁気光学記憶素子を提供すること
ができる。<Effects of the Invention> As explained above, the present invention provides that the first transparent dielectric film and the second transparent dielectric film are both formed of the same nitride material, and that the first transparent dielectric film The refractive index of the second transparent dielectric film is larger than that of the second transparent dielectric film.In other words, the structure is made by combining nitride films with different refractive indexes, so that it is possible to ensure the corrosion resistance of the recording medium and also to ensure good corrosion resistance. A magneto-optical storage element that can obtain information reproducing characteristics can be provided.
第１図は本発明に係る磁気光学記憶素子の一実
施例の構成を示す一部側面断面図、第２図はスパ
ツタ法によつて作製される膜の屈折率とガス圧の
関係を示す特性図、第３図は従来の磁気光学記憶
素子の構成を示す一部側面断面図である。
１……透明基板、３……希土類遷移金属合金薄
膜、６……レーザ光、７……第１の透明誘電体膜
（AlN膜）、８……第２の透明誘電体膜（AlN
膜）、９……反射膜（Al膜）。
FIG. 1 is a partial side sectional view showing the structure of an embodiment of the magneto-optical memory element according to the present invention, and FIG. 2 is a characteristic showing the relationship between the refractive index and gas pressure of a film produced by the sputtering method. 3 are partial side sectional views showing the structure of a conventional magneto-optical memory element. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 3... Rare earth transition metal alloy thin film, 6... Laser light, 7... First transparent dielectric film (AlN film), 8... Second transparent dielectric film (AlN
film), 9... Reflective film (Al film).
Claims (1)
移金属合金薄膜、第２の透明誘電体膜、反射膜を
この順に被覆してなる磁気光学記憶素子におい
て、 前記第１の透明誘電体膜及び第２の透明誘電体
膜を、共に同一の材料の窒化物で形成し、且つ前
記第１の透明誘電体膜の屈折率が前記第２の透明
誘電体膜の屈折率より大であるように構成したこ
とを特徴とする磁気光学記憶素子。 ２ 上記窒化物を窒化アルミニウムとしたことを
特徴とする特許請求の範囲第１項記載の磁気光学
記憶素子。 ３ 上記窒化物を窒化シリコンとしたことを特徴
とする特許請求の範囲第１項記載の磁気光学記憶
素子。[Scope of Claims] 1. A magneto-optical memory element comprising a transparent substrate coated with a first transparent dielectric film, a rare earth transition metal alloy thin film, a second transparent dielectric film, and a reflective film in this order, comprising: The first transparent dielectric film and the second transparent dielectric film are both formed of nitride of the same material, and the refractive index of the first transparent dielectric film is equal to the refraction index of the second transparent dielectric film. 1. A magneto-optical memory element, characterized in that the magneto-optical memory element is configured such that 2. The magneto-optical memory element according to claim 1, wherein the nitride is aluminum nitride. 3. The magneto-optical memory element according to claim 1, wherein the nitride is silicon nitride.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13943484A JPS6117236A (en) | 1984-07-03 | 1984-07-03 | Magnetooptic storage element |
| CA000462506A CA1224270A (en) | 1983-09-16 | 1984-09-05 | Magneto-optic memory element |
| US06/648,741 US4610912A (en) | 1983-09-16 | 1984-09-10 | Magneto-optic memory element |
| EP84306341A EP0139474B1 (en) | 1983-09-16 | 1984-09-17 | Magneto-optic memory element |
| DE8484306341T DE3481878D1 (en) | 1983-09-16 | 1984-09-17 | MAGNETOOPTIC STORAGE ELEMENT. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13943484A JPS6117236A (en) | 1984-07-03 | 1984-07-03 | Magnetooptic storage element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6117236A JPS6117236A (en) | 1986-01-25 |
| JPH0419618B2 true JPH0419618B2 (en) | 1992-03-31 |
Family
ID=15245102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13943484A Granted JPS6117236A (en) | 1983-09-16 | 1984-07-03 | Magnetooptic storage element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6117236A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62285256A (en) * | 1986-06-04 | 1987-12-11 | Konica Corp | Magneto-optical recording medium |
| JP2547768B2 (en) * | 1987-05-19 | 1996-10-23 | キヤノン株式会社 | Optical magnetic recording medium |
| JP2680586B2 (en) * | 1987-11-26 | 1997-11-19 | シャープ株式会社 | Magneto-optical storage medium |
-
1984
- 1984-07-03 JP JP13943484A patent/JPS6117236A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6117236A (en) | 1986-01-25 |
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