JPS60117433A - Electron beam recording disc - Google Patents

Abstract

PURPOSE:To read information without a detector of an electron beam arranged in a vacuum system by forming a material layer whose conductivity is changed from a low value to a high value. CONSTITUTION:Though an amorphous layer 23 of Te85Ge15 is amorphous and its conductivity is 10<-3>-10<-5>[1/OMEGA] when the amorphous layer 23 is in the vapor- deposited state, a crystallized high-conductivity part 23a (indicated by oblique lines in a figure) having 10-10<-1>[1/OMEGA] conductivity is formed when an electron beam 24 (having spot diameter 500Angstrom ) accelerated to 50keV is irradiated to a part of this layer 23 to crystallize the irradiated part. Next, when a relatively weaker electron beam 30 [having a 1/10 strength of the electron beam 24] is irradiated, a current is flowed to a current detector 33 because electrons are flowed through a conductive layer 22 in the high-conductivity part 23a. The current is flowed little to a low-conductivity part 23b which is amorphous still, and thus, information is read.

Description

DETAILED DESCRIPTION OF THE INVENTION +11 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 A technology using an optical disk for writing and reading records is known. To explain this with reference to the partially sectional perspective view of FIG. A portion 4 is formed. The position of the truck 3 is determined by (1) the front side, and whether or not an opening 4 is to be provided above a particular trunk is determined by a signal of "1" or "0". If so, recording is written by forming or not forming an opening in the track 4, and recording is read 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), the width is approaching the analytical limit of the light beam. It is not possible to narrow down the length to a size smaller than the diameter. Therefore, instead of light, an electron beam (elect
Ron beam, II! B) technology is being developed, in which the electron beam can be focused down to 500 human diameters, making it possible to write and read high-density records. A recording medium created using such an electron beam is called a BB disk, and the present invention relates to an improvement of the EB disk.

(3) Prior art and problems Conventional electron beam disks irradiate a weak electron beam (2) 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 conventional problems mentioned in 1., the present invention provides an electron beam recording disk that can be read without an electron beam detector placed in a vacuum system. The purpose is to

(5) Structure and object of the invention According to the present invention, a conductive layer is provided 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. This is achieved by providing an electron beam recording disk characterized by forming the following.

(3) (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 for electron beam recording. The idea was to perform writing by performing this phase transition, and to perform reading by irradiating a weak electron beam and using the difference in the ease with which electrons flow. The layers whose conductivity changes include TeGe, TeGeSn, TeGe5Se,
It was confirmed that a chalcogenide compound made of a combination of elements such as AsS and 5eGe is suitable.

Referring to FIG. 2, which shows a cross section of an embodiment of the present invention, a conductive layer 22 with a thickness of 100 μm is formed using aluminum (i) on a disk substrate (glass substrate) 21 with a thickness of 2Ill111.
It is formed by depositing by vacuum evaporation method. After that, the amorphous layer 23 (for example, Teei Ge 5 layers) is
It is formed to a thickness of 1,000 mm using a vacuum evaporation method.

Next, referring to Fig. 3, the amorphous layer of Te-qGe+ is amorphous in the as-deposited state, and the conductivity is (4) 10-3 to 1O-5 (1/Ω). However, an electron beam 24 (spot i) accelerated to 50 Keν is applied to a part of this layer.
When irradiating 500 fleas), the irradiated part can be crystallized, and the crystallized high conductivity part 23a (shown with diagonal lines in the figure) has a conductivity of 10° to 1O-1 (1/Ω). ) is produced. This is because 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 takes advantage of this fact.

Next, when a relatively weak electron beam 30 (see FIG. 4, 1/1'O 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).

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. 4, the EB switch 21 is installed in the electron beam device 31, and current flows through the shaft of the motor 32 to the current detector 33, allowing signal reading. In FIG. 4, 34 is an electron gun, 35 is a controller, 36 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 having high power and a short pulse width, the high conductivity part 23a is rapidly melted, and the melted part remains in the liquid phase and is 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, the present invention provides an electron beam recording disk that can be used in a vacuum device that does not include an electron beam detector, and (6) an octopus disk. It is possible to rewrite the record.

In the above explanation, the i-conductive layer and Tgh Ge
Although the amorphous layer of No. 15 is taken as an example, the scope of application of the present invention is not limited to that case, but also extends to cases where other materials are used.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a partial cross section of a conventional optical disc, FIGS. 2 and 3 are partial cross sectional views of the present embodiment, and FIG.
1 is a sectional view of the device for reading the disc shown in the figure; FIG. 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 (7)

Claims (1)

[Claims] 1. A disk for electron beam recording, comprising a conductive layer on a disk substrate and a material layer whose conductivity changes from low conductivity to high conductivity by electron beam irradiation on the conductive layer.