JPS6233760A - Manufacture of amorphous alloy film - Google Patents

Abstract

PURPOSE:To form the titled film exhibiting vertical magnetic anisotropy, by piling different kinds of metal element alternately as extremely thin atomic layer and diffusing atoms with each other from the boundary surface. CONSTITUTION:Different kind elements of >=two kinds such as Gd and Fe are vaporized alternately from crucibles 1, 1' arranged through a screen 2 to stack the elements alternately with a thickness of several atomic layers on a base plate S. Thereat, the plate S is moved alternately by a moving mechanism 5. Film thickness is measured by film thickness meters 6, 6' having about 1Angstrom resolving power. Atoms deposited on the plate S does not form film state, but form island state structure having spatial unevenness of fine particle state. Thus, the surface area in contact with different kind atomic layers is increased, and the atomic diffusion through the surface is carried out thoroughly. As a result, the vertical magnetized film of amorphous alloy having uniform property is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application 1] The present invention is directed to the formation of extremely thin atomic layers of different metal elements.
The present invention relates to a method for producing an amorphous alloy thin film that is made of these elements and exhibits perpendicular magnetic anisotropy by alternately depositing and stacking layers.

[Prior Art] Conventionally, in order to fabricate an amorphous alloy thin film having free time direct magnetic anisotropy by a vapor deposition method, different elements are evaporated simultaneously.
The original co-evaporation method has been adopted.

In co-evaporation method.

(1) In order to keep the composition ratio of the constituent elements of the film constant, it is necessary to control the evaporation rate of each element to keep it constant.

(2) Two evaporation sources cannot be placed directly under the substrate.

There were some important points such as: In order to satisfy the condition (1), the firing rate must be kept constant while taking into account the remaining amount of the evaporation source, which changes from time to time, and a complicated control system is required. Under condition (2), the fallen substance always enters the substrate obliquely. This often causes unnecessary magnetic anisotropy to be induced and compositional non-uniformity.

[Problem to be solved by the invention 1 Therefore, the purpose of the present invention is to eliminate these drawbacks.
Provided is a method for producing an amorphous alloy thin film in which the thickness of the vapor deposition is several atomic layers and the amorphous thin film is formed by utilizing the diffusion of the heteroatomic layer III and the spatial unevenness due to the island structure. There is a particular thing.

[Means for Solving the Problems 1] In order to achieve such an object, the present invention alternately laminates at least two or more types of different elements to a thickness of several tens of f layers on average. It is characterized by forming an amorphous thin film by rapidly diffusing atoms from the atomic layer interface of the elements.

[Function] According to the present invention, by alternately stacking several atomic layers with an average film thickness, a perpendicularly magnetized film exhibiting similar magnetism to an amorphous film obtained by simultaneous vapor deposition can be obtained. be able to.

[Example 1] Hereinafter, the ending 1jl will be explained in detail with reference to the drawings.

In the present invention, an example of an apparatus for performing cross-evaporation is shown in FIG. 1. In FIG. 1, 1 and 1' are crucibles containing evaporation sources. For heating the crucible 1, a resistance heating method or an electron beam heating method is used depending on the type of evaporation source. 2 is a screen, which allows two types of evaporated substances to pass through the substrate S.
Make sure it doesn't mix on top. Reference numeral 4 denotes a mounting portion for the substrate S, and the position of the mounting portion 4 is movable in the direction of the arrow by a moving mechanism 5. The film thickness gauges 6 and 6' measure the thickness of the film deposited on the substrate S, and the output is sent to the mobile device a5.
, and move the position l of the board S from the solid line position k to the broken line position t,
The film thickness gauges 6 and 6' are programmed with a predetermined thickness in advance, and several atomic layers can be laminated by measuring the average film thickness with the film thickness gauge for one person per resolution. I can do it.

Incidentally, each of the above-mentioned i'fil, 2, 4.5 and 6 is housed in the vacuum container 3.

In the present invention, in particular, 2 to 3 atomic layers are laminated on average. In this way, the deposited atoms do not form a film, but form an island structure having fine particle-like spatial irregularities. Therefore, the surface area in contact with the different atomic layers becomes large, atoms are sufficiently diffused through the surface, and an amorphous alloy thin film with uniform properties can be produced.

Furthermore, in order to form the deposited atoms into an island-like structure, it is preferable to cool the substrate S.

Examples of the present invention will be described below regarding an amorphous thin film in which gadolinium (Gd) and iron (Fe) are selected as elements.

In an embodiment of the present invention, gadolinium (Gd) and iron (Fe
) was selected as the element to fabricate an amorphous film.

A Cd--Fe amorphous orthogonally magnetized film exhibits a compensation temperature near room temperature when the component ratio of Gd and Fe is appropriately set, and therefore, it has been pointed out that it is useful as a magnetic recording material. : Figure 52 shows Fe (thickness of 4 people) and Gd (thickness of 4 people) at 200
The magnetization-temperature curve of a film with repeated layers is shown. As is clear from Fig. 2, in this example, the compensation temperature is near room temperature, and the magnetization is about 100 ers/cm3 near room temperature.
decreases to Generally, it is known that an Fe-Gd amorphous film becomes a perpendicularly magnetized film near the compensation temperature. In fact, when the magnetization hysteresis curve and the hysteresis curve due to the Kerr effect of the film shown in FIG. 2 are measured, the results are as shown in FIG. 3, indicating that the film is perpendicularly magnetized at room temperature.

The conditions for manufacturing the amorphous film shown in FIGS. 2 and 3 are as follows.

Vacuum degree during vapor deposition ~2 x 10 = Torr group
Plate glass (soft) Substrate temperature 150K ~ 200K and deposition rate
Measurements of 0.2 to 0.4 λ/sec were performed using a vibrating magnetometer in both FIGS. 2 and 3.

Next, we will show an example in which the component ratio of the film can be changed by changing the thickness of the atomic layer.As already mentioned, the compensation temperature is sensitively dependent on the component ratio of the film, When measuring the magnetization-temperature curve of a film made of 200 layers of Gd (6 layers thick), the compensation temperature moves to a higher temperature simply by increasing the thickness of Gd by 1 layer. This result suggests that by setting the film thickness of each element, a perpendicularly magnetized film having a predetermined compensation temperature can be fabricated.

In the present invention, due to the properties of the extremely thin vapor deposited film, due to the diffusion between atomic layers and the unevenness caused by the island-like vapor deposition surface, both elements are mixed randomly on the substrate S and exhibit the structure of an amorphous film. 0 In the manufacturing process of the present invention, there is no need to control the firing rate and only the film thickness needs to be measured, so the control system is simplified and reliability is high. It can be changed depending on the thickness of the atomic layer.

Furthermore, as can be seen from FIG. 1, the evaporation source is always located directly below the substrate S during vapor deposition, so that the influence of oblique incidence can be avoided.

[Effects of the Invention] As explained above, according to the present invention, by alternately stacking several atomic layers, an average film thickness similar to that of an amorphous film obtained by simultaneous vapor deposition can be obtained. A perpendicularly magnetized film exhibiting magnetism can be obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an example of an apparatus used to carry out the present invention, Fig. 2 is a characteristic diagram showing the magnetization-temperature curve of an Fe-Gd amorphous film, and Fig. 3 is a Fe-Gd amorphous film characteristic diagram. FIG. 3 is a characteristic diagram showing a magnetization hysteresis curve of a quality film and a hysteresis curve due to the Kerr effect. 1.1'... Crucible, 2... Screen, 3... Vacuum container, 4... Substrate attachment part, 5... Moving mechanism, 6.6'... Film thickness gauge, S. ··substrate. Patent Applicant Japan Broadcasting Association Agent Patent Attorney Yoshi Tani -: #Start a month /cq stuttering

Claims (1)

[Claims] An amorphous thin film is formed by alternately stacking at least two or more different elements to a thickness of several atomic layers on average, and diffusing atoms from the atomic layer interface of the different elements. A method for producing a characteristic amorphous alloy thin film.