JPS61208649A - Method for electron ray phase change type recording and reproducing and its apparatus - Google Patents

Abstract

PURPOSE:To attain write/erasure/read of information on a phase change type recording film by irradiating locally an electron ray on a phase change type recording thin film in pulsive way or with intensity change so as to heat/cool the thin film thereby causing the phase change. CONSTITUTION:A disc base 1 made of glass or aluminum on which a phase change type recording film 2 is coated in a thickness of 200Angstrom -5mum by the sputter, vapor-deposition or other general thin film forming method is used as a recording medium. The disc base 1 is loaded to a rotary axis 8 and driven while the side of the recording film 2 is placed upward. On the other hand, an electron gun 3 fixed to a slide axis 7 provided in parallel with the radius vector of the base 1 is used to irradiate the electron ray 5 on the recording film 2 on the base 1 in a pulsive way or with intensity change and the film face is heated/cooled locally to cause the phase change for information recording and erasure. Thus, the phase change type recording/erasure/reproduction is attained by using the converged electron ray.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a phase change type memory reproducing method and apparatus thereof, and is particularly suitable for high-density nonvolatile memory exceeding 101 bits per 1-d. The present invention relates to phase change recording, erasing and reproducing methods and devices thereof.In the present invention, interdiffusion occurs in composite films such as those that maintain an amorphous state and the atomic arrangement changes, and multilayer films. Phase changes are also included in the broad sense of phase change.

[Background of the invention]

As described in U.S. Pat. No. 3,530,441, a conventional phase change storage device uses an optical laser beam to heat a local phase change in a storage medium without causing any atomic movement. The state of change was used to store information. However, in this case, due to the wavelength limit of light, the minimum value of the light beam spot that can be converged is about 1 p in diameter, which is the limit of recording density using light! 01 bit/
It is d. However, in recent years, storage devices with even higher density are required to store large amounts of information.

On the other hand, regarding phase change recording using electron beams, although the above-mentioned US patent states that electron beams may be used in some cases, there is no mention of any specific examples, and there is no mention of specific examples. There is also no mention of a reproduction method, and no consideration was given to phase-change storage methods and devices that use electron beams for recording, erasure, and reproduction.

[Purpose of the invention]

The object of the present invention is to use an electron beam.

Writing (recording) information on the phase change recording film,
New storage and erasure with a storage density exceeding 101 bits/d.

An object of the present invention is to provide a regeneration method and apparatus.

[Summary of the invention]

In the present invention, the diameter of the electron beam is O.S.

More preferably, the electron beam is about 0.1 -, and the thin film is heated and cooled by locally irradiating the electron beam onto the phase change type recording thin film in a pulsed manner or with varying intensity. Does not produce phase changes such as solid phase■←→amorphous phase■, amorphous phase←→crystalline phase, crystalline phase■←→crystalline phase■, etc.
It is used to record or erase information, but reproducing memory takes advantage of the fact that the secondary electron emission ability differs between each phase, and distinguishes the phase depending on the amount of emitted secondary electrons.
In other words, information is discriminated.

[Embodiments of the invention]

The present invention will be explained in detail below using examples.

FIG. 1 is a schematic explanatory diagram of a phase change type recording/reproducing apparatus according to the present invention.

Recording is performed by depositing a phase change recording film 2 on a disk substrate 1 made of glass, aluminum, etc. to a thickness of 200 to 50 mm by sputtering, vapor deposition, or other general thin film fabrication methods. Use as a medium.

A protective film may be formed above or below the recording film, provided that the upper protective film is transparent to electron beams.

The above-mentioned phase change type recording film materials include As-8s-8-Go system of amorphous phase ■-amorphous phase ■ change type, 5n-To-8a system of amorphous poor phase-crystalline phase change type, crystalline Examples include a phase I-crystalline phase (I) change type Ag-Zn system.

The disk substrate 1 obtained as described above was mounted on the rotating shaft 8 with the recording film 2 side facing up, and
Rotate at a speed of p■.

On the other hand, an electron gun 3 fixed to a slide shaft 7 provided above the disk substrate 1 parallel to the radial direction of the substrate 1 converges an electron beam with a diameter of 0.24 onto the recording film 2 on the substrate 1. 5 is irradiated in the energy range of 0.1 to 100+++ W in a pulsed manner or with intensity changes, and the film surface is locally heated and cooled to cause a phase change, recording and erasing information. Accordingly, the electron @ 3 may be moved down along the slide axis 7, but it is more preferable to fix the electron gun 3 and move the one-rotation axis 8 in a direction perpendicular to the axis as recording progresses. .

This recorded information is reproduced by detecting the amount of secondary electrons from the substrate with a secondary electron detector 4 placed around the bottom surface of the electron gun 3 on the surface of the disk substrate 1. In this case, the electron gun, secondary electron detector, slide shaft, and disk substrate are usually arranged in a vacuum container.

In the CuBaTa film, the amount of secondary electrons from the amorphous phase is 5% of the amount of primary electrons, whereas the amount of secondary electrons from the crystalline phase is relatively small at 2%.

FIG. 2 (1) shows the CuBeTa amorphous recording film 2 on the substrate 1.
Using the apparatus shown in FIG. 1, an information spot array on which crystalline phase spots 9 with a diameter of 2 pm are recorded linearly at intervals of 0.54 is linearly illuminated with a primary electron beam 5 over the information spot array. In the figure, the emitted secondary electron beam 6 was detected by the secondary electron detector 4 after sweeping at a speed of m/sec, and the area surrounded by the dotted line indicates the area where no information was recorded. The measured relative amounts of secondary electrons from the crystal phase spot 9 and the amorphous phase region were as shown in FIG. 2 (2). From this, it was confirmed that the information string recorded on the recording film could be reproduced.

〔Effect of the invention〕

From the above explanation, 1. According to the present invention, there is provided a high-density recording and reproducing method and an apparatus thereof, which can realize phase-change type recording, erasing, and reproducing using a convergent electron beam, and has a recording density exceeding 101 bits/ai. can do.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a phase change storage device according to the present invention, and FIG. 2 is an explanatory diagram of an example of reproduction of recording spots. In fig. 1... Disc substrate 2... Phase change type recording film 3
...Electron gun 4...Secondary electron detector 5.
...Primary electron beam 6...Secondary electron beam 7...Slide axis 8...Rotation axis 9...Crystal phase spot

Claims (1)

[Claims] 1. A convergent primary electron beam having a predetermined energy and corresponding to predetermined multivalued or analog information is irradiated onto the surface of a phase change recording film formed on a substrate, and the recording film is Recording the information in the recording film or erasing the recorded information by locally heating and then cooling to cause a local phase change in the recording film, and irradiates the surface of the recording film on which the information is recorded with a focused primary electron beam having an energy that does not cause the phase change, and generates secondary electrons emitted from the surface of the recording film in response to the phase change. An electron beam/phase change type recording and reproducing method, characterized in that the multivalued or analog recording is reproduced by detecting a change in the amount of electrons. 2. In the electron beam/phase change recording and reproducing method according to claim 1, the phase change occurring in the recording film is amorphous phase I - amorphous phase II, amorphous phase - crystalline phase. or crystalline phase
An electron beam/phase change recording and reproducing method characterized by a phase change between I and crystal phase II. 3. An electron gun that irradiates a focused primary electron beam onto the surface of a phase-change recording film formed on a disk substrate, and detects the amount of secondary electrons emitted from the recording film surface by irradiation with the focused primary electron beam. a secondary electron detector arranged to rotate the disk substrate; a means for rotating the disk substrate; and a means for rotating the electron gun and the secondary electron detector relative to the disk substrate parallel to the radial direction of the substrate. What is claimed is: 1. An electron beam/phase change type recording/reproducing device, characterized in that the electron beam/phase change type recording/reproducing device is provided with means for moving the electron beam to