JPS5820732A - Preparation of magnetic thin film of oxide - Google Patents

Abstract

PURPOSE:To prepare a magnetic thin film of oxide useful as a high-density recording medium, by spattering alpha-Fe2O3 pieces or Fe3O4 pieces placed on an iron target in a given gas atmosphere. CONSTITUTION:alpha-Fe2O3 pieces or Fe3O4 pieces containing or not containing an additive are set on a Fe-target containing Fe or an additive. They are spattered in an atmosphere of a mixed gas of a neutral gas and an oxidizing gas or in an atmosphere of the oxidizing gas. A thin film of iron oxide of alpha-Fe2O3 or alpha-Fe2O3 containing the additive is formed on a base plate. Consequently, a magnetic thin film of oxide useful as a high-density recording medium is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an oxide magnetic thin film, and more particularly to a method for manufacturing an oxide magnetic thin film for high-density recording media used in magnetic disk drives and the like.

In order to improve the recording density in a magnetic recording device, a so-called coating medium in which a mixture of iron oxide fine particles and a binder is coated on the entire substrate has been widely used as a conventional magnetic recording medium. However, in the case of an integrated coating, it is extremely difficult to achieve uniform recording and reproducing characteristics even when the thickness is less than several thousand degrees.

Therefore, continuous thin film media, which can be easily made thin, are attracting attention as high-performance magnetic media to replace coating media. Although metal plated films have already been considered as continuous thin film media, oxide magnetic thin films have recently attracted attention. The reasons for this are: 1) the residual magnetic flux density is low, 2) it has high mechanical strength and chemical stability, and does not require the protective film required for thin metal films, and 3) the magnetic head-medium distance is small. This is because it is small in size and suitable for highly confidential recording and low cost.

Iron oxide thin films are mainly used as oxide magnetic thin films because they are easy to form, but their manufacturing methods include sputtering (reactive sputtering in an oxidizing or reducing atmosphere), reactive vapor deposition, and CD ( Chemical
al DeposH4on) method, CvD (Chemical
There are also methods such as the vaporized deposition method. Among these, the sputtering method has excellent advantages such as good adhesion between the medium and the substrate, the ability to form a strong thin film, and suitability for continuous production.

As a reactive sputtering method in an oxidizing atmosphere in this sputtering method, there is a method called an "indirect method."

This method uses a Fe f target and sputters in a region with a high oxygen partial pressure, and once α-p6zQa is deposited on the substrate.
After the thin film is deposited, it is completely reduced to form Fe5Q4.

Formation of α-FegQs by this “indirect method” brings the Fe atoms into a highly oxidized state, so the slower the film deposition rate, the more reliably the conversion to α-FezQs can be achieved. In order to increase the overall production productivity, the overall deposition rate must be increased and, as a result, the oxygen partial pressure must also be increased. However, if the oxygen level increases, you may feel vomiting.
The degree of oxidation on the e-metal surface becomes flat, and once the surface layer becomes α
-F(zQx), the sputtering rate of the target decreases.Also, if the degree of oxygen is small relative to the film deposition rate, unoxidized substances may be mixed into the α-Fezes film. Feig
Even if n is used, substances with a low degree of oxidation such as FeO are generated, and γ
Even if -F'ezOa is formed, the r-FesQs formation may be incomplete, resulting in a film with poor properties, and it has often been difficult to stably form α-F8203 under high sputtering rate conditions.

The present invention aims to solve all of these drawbacks, and its purpose is the same as that of the "indirect method" (Fet target is used, but it is possible to form an α-FegQa film with stable production margin and anvil in high-speed sputtering. There is a whole way to offer you.

The present invention provides α
- By arranging a Fears piece or a Fe5ea piece or an α-Fears piece or Fea041r containing an additive, and sputtering in a mixed gas atmosphere of a neutral gas and an oxidizing gas or in an oxidizing gas atmosphere,
It is characterized in that an iron oxide thin film of α-FezQa or α-Fezes containing additives is formed on the entire substrate. According to the present invention, it is possible to obtain an oxide magnetic thin film that can be stably and efficiently formed even at high sputtering rates, such as those used in magnetic disk media and the like.

Next, the present invention will be described in detail with reference to Examples.

Example 1 A commercially available two-pole sputtering apparatus was used, ref was used as the target as shown in the table, and a small piece of α-FexO (lXlcIn) was placed on 30 inches of the target area.
, thickness 21111) T+- was dispersed, and preliminary sputtering was performed for a total of 30 minutes under the conditions shown in the table, and then main sputtering was performed on an alumite-coated aluminum alloy substrate at a deposition rate of 130, p, /xm. A 18 μm film was obtained.

This film was confirmed to be α-pe zQx based on electron diffraction and film resistance values.

Example 2 FeK1 was used on the same equipment as in Example 1, as shown in the table.
．． A small piece of peaQ4 doped with 5% cobalt vi-1,5 on top of the target doped with 5% (1)
<1m, thickness 2mm) fully dispersed, preliminary sputtering and then main sputtering to deposit 0.18μ on an alumite coated aluminum alloy substrate at a deposition rate of 14OA/mm.
A film of m was formed. Based on electron diffraction and resistance values, this film was α-Fetus 69. As a result of reducing this film in a hydrogen atmosphere at 310°C for 2 hours, the residual magnetic flux density was 3200 Gauss, the coercive force was 450 Oersted, and the resistivity was ρ5×10−2Ω.
- It became the so-called p6iQ4 membrane. Furthermore, this Fea04
When the film was oxidized for 1 hour in the atmosphere at -320°C, the residual magnetic flux density was 3100 Gauss, the coercive force was 600 Oersted,
A γ-Fe20a film with a specific resistance ρ>1×1030 was obtained.

Example 3 In order to increase the rate of sputtering, magnetro/
As shown in the table, α-Fe corresponding to 40 inches of the target area was
A piece of zOa (IXI cm, thickness 2 m) was placed under the magnetron discharge ring in the area with the highest sputtering rate, and after a preliminary sputtering session of 30 minutes, main sputtering (rate 400 A/, 1) was performed. A 18 μm membrane was obtained.

This film was found to be α-FezO based on electron diffraction and resistivity measurements.
It was confirmed that it was a.

Example 4゜Same as Example 3, magnetron type sputtering device i
A small piece of Fear4 (IXlcrR, 2 m thick) f? was used on the Fe target as shown in the table. The sputtering was performed under a Gnetron discharge ring, and preliminary sputtering was performed for 30 minutes in a pure oxygen atmosphere, followed by main sputtering (rate 350 A/11131) w 0.1
A membrane of 8 μm was obtained. Electron diffraction and resistivity measurements showed that this film had α-p620! It was confirmed that it was marked +.'fc.

In the above examples, α-Fezoa pieces and Fea
s4 pieces are placed on all targets, but at this time, α-1i'62 pieces are placed on all targets to prevent cracking or deterioration of α-FezOa pieces and FeaOa pieces due to heat generated during sputtering.
Adhering a good thermal conductor to the Qa or Fe5Oa t-Fe l-get surface has a great effect on improving the reproducibility of film formation. In this disaster example 3.4, the α-Fez08 and Fe3O4 devices are placed under the magnetron discharge signal, but this is possible by placing the target formation or everything close to it in the largest area of the sputtering rate. This is because it can be easily converted into α-FezOa and the margin increases.

-Also, conventionally, when using a large target of α-Fe20a, cracking due to heat was a serious problem, but according to the present method, such a problem did not occur.

As mentioned above, α-Fezes pieces or Fe5Oa pieces, or α-FezOa pieces or Fs104 containing additives are placed on the target containing all iron or additives.
α-FezQa or α-Fe containing all additives can be sputtered in a mixed atmosphere of neutral gas and oxidizing gas or in an oxidizing gas atmosphere.
zOa iron oxide thin film is formed directly on the entire substrate, and then
According to the method for manufacturing an oxide magnetic thin film according to the present invention, in which the thin *'t-reduction is performed to obtain Fe104, and further oxidation is performed to obtain γ-FezOs, film formation is faster than the conventional method using an Fe t-target. When the manufacturing margin is completely increased, a higher deposition rate can be obtained, and the effect is that the entire recording medium for high-density recording can be easily formed with high manufacturing efficiency.

Claims (2)

[Claims] (1) α-p on iron target containing iron or additives
If ezQs pieces or Fe104 pieces or α-J'ezQs pieces containing additives are placed, all 5 FeaOa pieces are arranged,
Sputtering is performed in a mixed gas atmosphere of neutral gas and oxidizing gas or in an oxidizing gas atmosphere. Especially α-Pet's or α-Fego with additives.
A method for manufacturing an oxide magnetic thin film comprising forming an iron oxide thin film of 5 t % on a 5-it-substrate. (2) α-p on iron targets containing iron or additives
ezOs pieces or Fe504 pieces or α-FezOa pieces or pea94 pieces containing additives are arranged and sputtered in a mixed gas atmosphere of neutral gas and oxidizing gas or in an oxidizing gas atmosphere.
- Form an iron oxide thin film of α-F62Q3 containing Pesos or sulfur on the entire substrate, and reduce the thin film to
A ferromagnetic thin film containing 4e as the main component is formed, and further oxidized to form γ
- A method for producing an oxide magnetic thin film characterized by Fe and Os.