Transcript Two-layer ultra-high density x-ray optical memory - X

Two-layer ultra-high density
x-ray optical memory (X-ROM)
 In a glance:
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Optical system of
typical drive.
DVD Innovations.
What’s next ?
X-ray optical memory.
Zone-plate-array
lithography.
X-ROM characteristic
function.
Our answer to the
question above.
X-ROM Technology
presenting author:
Dr. Hakob P. Bezirganyan,
X-ROM, Inc.
[email protected]

co-authors:
Siranush E. Bezirganyan,
Hayk H. Bezirganyan (Jr.),
Petros H. Bezirganyan (Jr.).
Copyright © 2006 X-ROM, Inc. All rights reserved.
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Main References
1.
2.
3.
4.
Bezirganyan H.P., Bezirganyan P.H., Phys. Stat.
Sol. (a), 1988, 105, 345-354.
Bezirganyan H.P., Phys. Stat. Sol. (a), 1988, 109,
101-110.
Bezirganyan H.P., Bezirganyan H.H. (Jr.),
Bezirganyan S.E., Bezirganyan P.H. (Jr.), Opt.
Commun., 2004, 238/(1-3), 13-28.
Bezirganyan H.P., Bezirganyan H.H. (Jr.),
Bezirganyan S.E., Bezirganyan P.H. (Jr.),
Mossikyan Y.G., J. Opt. A: Pure Appl. Opt., 2005,
7/10, 604-612.
X-ROM Technology
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20th Century: The Compact Disc
 Patented in 1970 by James T. Russell as a means
for durable audio data storage.

Mass production starts in 1985 by Philips and
Sony.
 Data Density: ~ 1Mbyte/mm2
X-ROM Technology
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Optical system of typical drive
 Conventional optical
storage uses a
focused laser beam
to access individual
bits in a single layer.
Optical head reads
the information by
capturing reflected
light as the laser
beam travels across
the pits and lands.
 Changes in light intensity are interpreted as 0’s and 1’s.
 Pits can be either dark on bright background or reversed.
X-ROM Technology
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Improvements of CD → to DVD
(pit dimensions etc.)
 Innovations:
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X-ROM Technology
Dual layer
Increased numerical aperture
Decreased depth of focus
Improved signal to noise
Data Density: ~7 MByte/mm2
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Numerical Aperture (NA)
 The diameter of the diffraction limited spot is directly
proportional to the laser wavelength and inversely
proportional to the numerical aperture (NA) of the
imaging lens.
X-ROM Technology
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Solid-Immersion Lens (SIL)
 A solid-immersion lens (SIL) can increase the
effective Numerical Aperture, which, consequently,
gives the possibility to increase the density of data
carrier elements. However, this requires an
evanescent coupling between the SIL and disk.
X-ROM Technology
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Comparison Table
Feature
DVD
CD
Substrate Dia./Thick. 120 x 1.2 mm
120 x 1.2 mm
Sides
1 or 2
1
Layers per side
1 or 2
1
Capacity (GB)
4.7, 8.54, 9.4, 17
0.7
Track Pitch (micron)
0.74
1.6
Minimal pit length
(micron)
0.44
0.83
Linear scan velocity
3.6 m/s
1.3 m/s
Laser wavelength
635 nm
780 nm
Numerical Aperture
0.6
0.45
Spot Size
1058 nm
1733 nm
X-ROM Technology
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What’s next ?
0.7 GB
9 GB
50 ~ 100 GB
?
?
X-ROM Technology
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An example of the ultrahigh density
digital data carrier
 Most important aspect of nanotechnology applications in
the information ultrahigh storage is the miniaturization of
data carrier elements of the storage media with
emphasis on the long-term stability.
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An example:
Let the single-bit linear size Lbit = 10 nm and the
bit spacing Δlbit = 10 nm, then a memory capacity of
the ultrahigh storage material with surface area S = 1
cm2 is equal to:
2
1bit  S / L bit   l bit  
 10 14  bit  nm 2 / 10 nm  10 nm  
2
 25 10 10 bit  0.23 Tbit .
X-ROM Technology
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An example of the ultrahigh density
digital data carrier
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In considered example,
an ultrahigh density
two-sided digital data
storage carrier with two
layers per each side
and 12 cm of edge size
of the square shaped
substrate has following
capacity:
4  12 cm  12 cm  0.23  Tbit / cm 2  
132 .48 Tbit  16 .56 Tbyte  17 000 GB .
X-ROM Technology
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Data recording nanotechnology based
on Zone-plate-array lithography (ZPAL)
 ZPAL
is developed by
Massachusetts
Institute of
Technology,
USA.
 ZPAL uses:
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a narrow
bandwidth
source,
an array of diffractive lenses (e.g., Fresnel zone plates)
focuses an array of on-axis spots on the surface of a
wafer coated with photosensitive material (photoresist),
a scanning stage, to print arbitrary patterns within a
photoresist without a mask.
X-ROM Technology
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Digital data read-out procedure using
the glancing-angle incidence x-rays
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X-rays reflection from
the proposed X-ROM,
takes place either by
the GIXB in first silicon
layer or the difference
in refractive indexes of
the second silicon
layer and of embedded
germanium domains.
4  12 cm  12 cm  0.23  Tbit / cm 2  
132 .48 Tbit  16 .56 Tbyte  17 000 GB .
X-ROM Technology
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X-ROM Characteristic Function
 A characteristic function ΔR = (R2 – R)
is introduced for the proposed X-ROM,
where:
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R2 is the reflectivity coefficient of the x-ray
plane wave reflected from or diffracted by
the X-ROM wafer.
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R is the reflectivity coefficient of the x-ray
plane wave reflected from the nanosized
mirror material.
X-ROM Technology
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X-ROM Characteristic Function
 The minimum values of X-ROM characteristic function
are most appropriate for the proposed digital data
read-out procedure.
X-ROM Technology
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15
Our point of view on what
could be next:
9 GB
50 ~ 100 GB
17 000 GB
X-ROM
two-layer
two-sided
X-ROM Technology
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Thank you
We hope that you’ve enjoyed this presentation, and that
we were able to answer some of your questions about
the X-ROM Technology, and convey the potential and the
impact this new technology can have on the future of
data storage.
Sincerely,
X-ROM R & D Team
X-ROM Technology
Copyright © 2006 X-ROM, Inc. All rights reserved.
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