Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1997-11-10
2001-10-30
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S825000, C205S068000, C205S078000
Reexamination Certificate
active
06308405
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to media such as recording medium, electrode substrate, etc., processes for producing these, recording device, the reproducing device which perform recording, reproducing with a probe electrode by use of such recording media, information processing devices including recording reproducing devices, and information processing methods including recording method, recording-reproducing method, recording-reproducing erasing method.
2. Related Background Art
In recent years, use of memory materials is at the center of electronics industries such as computers and their related instruments, video disc, digital audio disc, etc., and developments of such materials have been progressed extremely actively. The performances demanded for memory materials depend on the uses, but may generally include:
(1) high density and large recording capacity;
(2) rapid response speed of recording and reproducing;
(3) small consumption power;
(4) high productivity and low cost, etc.
Up to date, there have been semiconductor memory and magnetic memory utilizing magnetic materials or semiconductors as the base material, but with the progress of laser techniques in recent years, inexpensive and high density recording media by optical memory with the use of organic thin films such as of organic dyes, photopolymers, etc., have been launched in the field.
On the other hand, recently, a scanning tunnel microscope (hereinafter abbreviated as STM) which can directly observe the electron structure of the surface atoms of a conductor has been developed (G. Binnig et al., Phys. Rev. Lett., 49, 57 (1982)), and it has become possible to perform measurement of real space images with high resolving power regardless of whether they may be single crystals or amorphous, and still having the advantage that observation is possible at low power without causing a damage with current to the sample. Further, it can be actuated in the air and used for various materials, and therefore a wide range of applications have been expected therefor.
STM utilizes the phenomenon that a tunnel current flows when a probe of a metal (probe electrode) and an electroconductive substance are approached to a distance of about 1 nm with a voltage applied therebetween. Such current is very sensitive to the distance change between the two. By scanning the probe so as to constantly maintain the tunnel current, various information concerning the whole electronic cloud in the real space can be read. In this case, the resolving power in the interplanar direction is about 0.1 nm.
Therefore, by applying the principle of STM, it is possible to perform high density recording and reproducing sufficiently at atomic order (sub-nanometer). For example, in the recording and reproducing device disclosed in Japanese Laid-open Patent Publication No. 61-80536, the atomic particles adsorbed onto the medium surface are removed by electron beam, etc., writing is effected and the data are reproduced by STM.
There has been proposed the method of performing recording and reproducing by STM with the use of a thin film layer of a material having the memory effect of the switching characteristics of voltage and current, such as &pgr; electron type organic compound or a chalcogenide compound (Japanese Laid-open Patent Applications Nos. 63-161552, 63-161553). According to this method, if the bit size of recording is made 10 nm, high capacity recording and reproducing as much as 10
12
bit/cm
2
are possible.
FIG. 7
shows a constitutional example of the information processing device in which STM is applied. In the following, description is made by referring to the Figure.
101
is a substrate,
102
an electrode layer of a metal, and
103
a recording layer.
201
is an XY stage,
202
a probe electrode,
203
a support for the probe electrode,
204
a Z-axis linear actuator for driving the probe electrode in the Z direction,
205
,
206
are linear actuators for driving the XY stage in the directions X, Y, respectively and
207
is a pulse voltage circuit.
301
is an amplifier for detecting the tunnel current flowing from the probe electrode
202
through the recording layer
103
to the electrode layer
102
.
302
is a logarithmic reducer for converting the change in tunnel current to a value proportional to the gap distance between the probe electrode
202
and the recording layer
103
,
303
a low region passing filter for extraction of the surface unevenness component of the recording layer
103
.
304
is an error amplifier for detecting the error between the reference voltage V
REF
and the output from the low region passing filter
303
,
305
a driver for driving the Z-axis linear actuator
204
.
306
is a driving circuit for performing positional control of the XY stage
201
.
307
is a high region passing filter for separating the data component.
FIG. 8A
shows a sectional view of the recording medium of the prior art example and the tip of the probe electrode
202
.
401
is the data bit recorded on the recording layer
103
, and
402
is the crystal grain when the electrode layer
102
is formed on the substrate
101
. The size of the crystal grain
402
is about 30 to 50 nm by use of conventional vacuum vapor deposition method, sputtering method, etc. as the preparation method of the electrode layer
102
.
The gap between the probe electrode
202
and the recording layer
103
can be kept constant by the circuit constitution shown in FIG.
7
. More specifically, by detecting the tunnel current flowing between the probe electrode
202
and the recording layer
103
, and the value after passing the current through the logarithmic reducer
302
and low region passing filter
303
is compared with the reference voltage, and by controlling the Z-axis linear actuator
204
supporting the probe electrode
202
so that the comparative value approaches zero, the gap between the probe electrode
202
and the recording layer
103
can be made substantially constant.
Further, by driving the XY stage
201
, whereby the surface of the recording medium is traced with the probe electrode
202
, and the high region frequency component of the signal at the â ; point in
FIG. 7
to enable detection of the data in the recording layer
103
.
FIG. 9A
shows the signal intensity spectrum for the frequency of the signal at the â ; point at this time.
The signals of the frequency components of f
o
or less are due to gentle undulation of the medium on account of warping, distortion, etc. of the substrate
101
. This signal with f
1
as the center is due to unevenness of the surface of the recording layer
103
, primarily on account of the crystal grain
402
formed during formation of the electrode material. f
2
is the conveying wave component of the recording data, and
403
the data signal band. f
3
is the signal component formed from the atomic, molecular arrangement in the recording layer
103
.
When the recording medium shown in the prior art example was used, the following problems were involved.
For performing high density recording by making available high resolving power, which is the specific feature of STM, the data signal band
403
must be placed between f
1
and f
3
. In this case, for separating the data components, a high region passing filter
307
in
FIG. 7
with a shielding frequency f
c
is employed. However, the tail portion of the signal component of f
1
overlaps the data signal band
403
. This is because the signal component of f
1
is caused by the crystal grain
402
in the electrode layer
102
, and the recording size and the bit interval of the data are approximately 1 to 10 nm as compared with the crystal grain
402
of 30 to 50 nm.
For this reason, when high recording and reproducing is conducted, S/N ratio of recording reproducing is lowered to make the error ratio of reading data markedly high.
FIG. 8B
shows a sectional view of the recording medium having a track and the tip of the probe electrode
202
.
104
is a track.
In
FIG. 9B
, f
T
is a tracking signal. Although not
Eguchi Ken
Hatanaka Katsunori
Kawada Haruki
Kawade Hisaaki
Kawagishi Hideyuki
Canon Kabushiki Kaisha
Chang Rick Kiltae
Fitzpatrick ,Cella, Harper & Scinto
Young Lee
LandOfFree
Process for preparing an electrode substrate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing an electrode substrate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing an electrode substrate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2580544