JPH0462138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an electron beam recording disk, and more particularly to a large capacity recording disk in which an electron beam is used for writing and reading.

(2) Background of the technology The technology of using optical disks for writing and reading records is known. To explain this with reference to the partially sectional perspective view of FIG. An opening 4 is formed. Assuming that the position of the track 3 is determined in advance, and whether or not an opening 4 is to be provided above a particular track is made to correspond to signals of "1" and "0" in a digital manner, Recording is performed by forming or not forming an opening in the track 4, and reading is performed by detecting this.

The width of the groove 2 has been miniaturized to about 0.7 μm to 0.8 μm, but when writing and reading records using a light beam (for example, a laser beam), it is approaching the analytical limit of the light beam, and the width of the light beam is reduced to the above-mentioned length. cannot be narrowed down to a diameter smaller than the diameter of Therefore, technology is being developed that uses electron beams (EBs) instead of light, and since electron beams can be focused down to a diameter of 500 Å, it becomes possible to write and read high-density records. A recording medium created using such an electron beam is called an EB disk, and the present invention relates to an improvement of the EB disk.

(3) Prior Art and Problems Conventional electron beam disks emit a weak electron beam and read out the secondary electrons reflected by a detector. Therefore, the readout detector had to be placed in the vacuum system, which required extra volume in the vacuum system. Therefore, there is a need for an electron beam recording disk that can detect the secondary electrons without using a detector placed in such a vacuum system.

(4) Purpose of the Invention In view of the above-mentioned conventional problems, the present invention aims to provide an electron beam recording disk that can be read without an electron beam detector placed in a vacuum system. This is the purpose.

(5) Structure of the Invention According to the present invention, this object is to provide a conductive layer on a disk substrate and a material layer on the conductive layer whose conductivity changes from low conductivity to high conductivity by electron beam irradiation. Recording is performed by forming a high conductivity part in the material layer by electron beam irradiation, and reading is performed by irradiating the material layer with a second electron beam weaker than the electron beam to form a high conductivity part in the material layer. This is achieved by providing an electron beam recording disk characterized by a configuration in which a current generated by electrons flowing from a conductive portion through the conductive layer is detected.

(6) Examples of the invention Embodiments of the present invention will be explained in detail below with reference to the drawings.

The present inventor provided a layer whose conductivity changes from low conductivity to high conductivity due to phase transition between amorphous and crystalline on the conductive layer of the disk as an electron beam recording disk. We considered writing by performing a phase transition, irradiating a weak electron beam, and reading by the difference in the ease with which the electrons flow. And as a layer whose conductivity changes,
It was confirmed that chalcogenide compounds made from combinations of elements such as TeGe, TeGeSn, TeGeSSe, AsS, and SeGe are suitable.

Referring to FIG. 2, which shows a cross section of an embodiment of the present invention, a disk substrate (glass substrate) 21 with a thickness of 2 mm is shown.
A conductive layer 22 having a thickness of 100 μm is formed thereon by depositing aluminum (Al) using a vacuum evaporation method. After that, an amorphous layer 23 (for example, Te ₈₅
Ge ₁₅ layer) is formed to a thickness of 1000 Å by vacuum evaporation.

Next, referring to Figure 3, the amorphous layer of Te ₈₅ Ge ₁₅ is amorphous in the as-deposited state and has a conductivity of 10 ^-3 to 10 ^-5 [1/Ω]; When a part of the layer is irradiated with an electron beam 24 (spot diameter 500 Å) accelerated to 50 KeV, the irradiated part can be crystallized, resulting in a crystallized highly conductive material with a conductivity of 10° to 10 ^-1 [1/Ω]. A section 23a (shown with diagonal lines in the figure) is created. This takes advantage of the fact that amorphous materials have high resistance, but when they are irradiated with a low-power, long-pulse electron beam, they are slowly cooled and the amorphous material turns into a crystalline material. It is.

Next, when a relatively weak second electron beam 30 (see FIG. 4, 1/10 of the intensity of the electron beam 24) is irradiated, electrons flow through the conductive layer 22 in the high conductivity part 23a, so that the current detector 33 (see Figure 4)
A current flows through. Since little current flows through the low conductivity portion 23b, which remains amorphous, reading can be performed. The structure of the embodiment of the present invention formed in this way is the same as the structure of the optical disk shown in FIG. 1, but the difference is that the density is increased.

In operation, as shown in FIG.
The signal can be read out. In FIG. 4, 34 is an electron gun, 35 is a controller, and 3
6 is an electron lens, 37 is a deflector, and 38 is an exhaust pump. In the prior art, the secondary electron detector is designated by the reference numeral 39 and is arranged as shown by the dotted line. Since the illustrated device is well known, detailed description thereof will be omitted.

In this embodiment, recording can be rewritten. That is, when the high conductivity part 23a is irradiated with an electron beam with high power and short pulse width, the high conductivity part 23a is rapidly melted, and the melted part remains in the liquid phase and is rapidly cooled to room temperature, so that it becomes amorphous. The state returns to the state shown in FIG. 2, and information can be recorded again.

(7) Effects of the Invention As described in detail above, according to the present invention, there is provided an electron beam recording disk that can be used in a device that does not include an electron beam detector in a vacuum device, and this disk can also be used to rewrite records. is possible.
In the above explanation, the Al conductive layer and Te ₈₅
Although an amorphous layer of Ge ₁₅ is taken as an example, the scope of application of the present invention is not limited thereto, but also extends to cases where other materials are used.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a partial cross section of a conventional optical disk, FIGS. 2 and 3 are partial cross sections of the present embodiment, and FIG. 4 is a cross section of the device for reading out the disk shown in FIG. It is a diagram. 21... Glass substrate, 22... Conductive layer, 23
...Amorphous layer, 23a...High conductivity part, 23b...
...Low conductivity part, 24...Electron beam, 30...Electron beam, 33...Current detector.

Claims (1)

[Scope of Claims] 1. A conductive layer is formed on a disk substrate, and a material layer whose conductivity changes from low conductivity to high conductivity by electron beam irradiation is formed on the conductive layer. Reading is performed by forming a high conductivity part in the material layer by beam irradiation, and reading is performed by irradiating the material layer with a second electron beam weaker than the electron beam and passing through the conductive layer from the high conductivity part. An electron beam recording disk characterized by a configuration that detects the current generated by flowing electrons.