A NOVEL TECHNOLOGY FOR
THE PRODUCTION OF STRUCTURED NANODIMENSIONAL THIN FILMS
AND USER DEFINED GEOMETRIES.
U.S. Patent No.
6,541,392
The invention under discussion
enables the engineered deposition of high performance ultra thin coatings
from a wide variety of materials. The coatings are
structured and user defined in terms of geometry and chemical composition
in all three dimensions. The depositions produced enable
miniaturization, enhancement of optical, electro-magnetic and
mechanical properties, user defined geometries and a profusion of
surface specific phenomenon. The technology is capable
of producing ultra-thin products with superior performance in
a wide variety of engineered geometries currently unavailable
in the market. The improved performance is due
to the engineered nature of the deposition. Coatings of this type also
present significant cost savings, as they require reduced amounts
of deposited materials in order to achieve the required performance
specifications. This technology is applicable to a wide
variety of industries and is currently available for license.
SAMPLE APPLICATIONS
Contact wear resistance is of significant interest
to the electronics industry. If one desires a wear resistant gold
coating, by the application of this technology, one
could deposit a combination of TiN (titanium nitride) and Au
(gold) producing a deposition that retains the electrical and
optical performance of gold, coupled with the strength and
toughness of TiN.
Alternatively,
if a precision polishing surface is required, the above structure can
be etched to remove the Au, thereby producing a near perfect TiN polishing
surface. If a carbide polishing surface is preferable, the initial
deposition can be produced with the appropriate carbide system.
Furthermore, if a nano-dimensional template or a nano-dimensional
filter is required the TiN and Au can be deposited in a cylindrical form.
Where upon etching the Au results in a TiN structure
with cylindrical pores along one axis.
If nano-dimensional wires are desired, they can
be produced by capillary action or by simple choice of the deposition materials
and appropriate etching.
The technology is capable of producing ultra-thin products
with superior performance in a variety of engineered geometries.
The improved performance is due to the engineered
nature of the deposition.
SCIENTIFIC PRINCIPAL
The underlying principle of the invention revolves around the mechanisms
of stress reduction in thin films. Thin films, like those found
in conventional deposition technologies, are prone to deformation and reduced
performance due to the stresses of different crystal lattice parameters.
These lattice differentials are present between the different components
in a deposition, the substrate, and the deposition itself. These
stresses are a function of the mobility of adatoms within the deposition
and the affinity of a species to agglomerate with itself and other species.
Another way of viewing this is, how willing is a species to combine with
other adatoms (both of the same and different species). It is well
known that just a few percent difference in lattice parameters creates huge
stresses in a film. These stresses are a natural occurrence and are a function
of how mobile a species is, its surface activity, and the associated chemical
and physical potential energies. These parameters are well
known, and for most species, can be found in the appropriate literature.
Operators in the field of deposition technology do all that is possible
to minimize these effects in order to produce depositions with the minimum
amount of stress. The technology presented here utilizes these stresses
and by defining the deposition parameters, encourages these stresses to produce
depositions with a structured nature. In the application of this technology
we are not fighting the inherent nature of the materials and their behavior.
Rather, this technology encourages the stress evolution and the natural
stress relief mechanisms resulting in controlled growth into both the horizontal
and vertical planes.
This methodology can be realized by the precise control of the deposition
parameters, which enables and defines the physics of stress expulsion.
Thus, consecutive depositions of materials X, Y, and
Z etc. at proper conditions produce 3D anisotropic structures defined by
the user on a nanometer to micron scale. The structure formed is a function
of the deposition parameters of each individual component.
PROOF OF CONCEPT
In one of our test samples, we selected a two-component system comprised
of gold (Au) and titanium nitride (TiN).
In general, there are three possible structures
for consecutive coatings of two different materials; a multilayer structure,
a non-structured deposition and by application of this technology a three
dimensional engineered structure. The deposition parameters were established
so that a carrot like structure was deposited.
The resulting deposition was analyzed by scanning
electron microscopy (SEM) and X-ray diffraction (XRD). In the case of
thin films, 200 300 nanometers, XRD provides information about the structure
of all metals or compounds in the film, in this case Au and TiN.
The initial XRD trace recorded both Au and
TiN. If we selectively etched one of the components, for example Au; we
will see a XRD spectra for TiN, only if the coating has a carrot-like structure.
If the structure was multilayered or non-structured, etching
would remove only the surface Au and a gold XRD trace would also be recorded.
In order to demonstrate that the deposition was indeed carrot like,
we chemically etched Au from the deposition using a mixture of hydrochloric
and nitric acids. The deposition
was then re-analyzed by XRD.
The resulting XRD, figure 5, showed no trace of gold, which proves that
the deposition was structured as defined by the process.
Figure 4 represents the deposition build up as a function of material.
Figure 5 represents the XRD diffraction
patterns before and after chemical etching
APPLICATIONS
This technology is applicable over a very wide range of novel applications
as well as an enhancement and replacement of existing technologies. The
ability to utilize this technology on existing equipment, with small modifications,
enables its wide range application in a cost-effective manner.
A short list of potential applications includes:
Wear resistant conductive thin films
Applications abound in the electronics industry, telecommunications and
systems utilizing electrical and mechanical contacts.
Wear resistant decorative plating
Coatings for jewelry, silverware and decorative fixtures.
This technology enables high wear resistance, the ability to deposit high
levels of cost effective materials and low levels of expensive materials
with increased performance while maintaining the appearance of precious
metals.
Strength enhanced coatings
This technology can be applied to stamping and cutting
applications, automotive, aerospace, medical and structural components.
Cutting tools can be produced with cost effective materials
and subsequently deposited with a structured material to increase strength
and toughness. Used tools
can be re-coated to original dimensions.
Structured depositions could greatly prolong
tool life. Coatings
may prolong and protect CD's, by itself a multi-billion dollar industry.
Other applications include medical tools,
precision mechanical tools, drill bits, coatings for machined parts used
in abrasive environments, bearings, and optical coatings to name but a
few.
Abrasive thin film media
With the development of miniaturized technology, finely
controlled abrasive thin films will enable extremely fine control over
polishing depths and defect sizes.
Abrasive thin films of this type may find many new applications.
Wear resistant optical
The introduction of fiber optics to replace conventional connection and
transmission lines may require novel structures to enable contacts, switches
and protective coatings.
Ultra thing coatings may also enable user-defined applications such as
corrosion resistance using silver nitride and integration possibilities.
User defined coatings may also enable the coating of
engineered systems to replace breakable glass and to facilitate
optical to electrical junctions.
Quantum Dot arrays
This is a high technology application related to the
new development in the nano-structured materials.
This is a relative new field with applications in R
& D, medicine, drug delivery and novel optical applications.
Some examples include nano-dimensional reversible media,
field emission nano-tip arrays based on metal dots, diamond like materials
and thermo-stable quantum dot arrays.
Optical coating with 3D anisotropy
With the expansion of the space program and ballistic
missile technologies, reflective coatings for harsh environments have become
a concern. Optical reversible media for harsh environments, polarized reflective
films, interference filters, and cylindrical magnetic optical domains are
possible with this deposition technology.
Nanodimensional templates
Nanodimensional-template structures or filters produced
from nitrides, oxides, carbides, silicides or other materials are direct
applications of this technology.
Applications such as nano-dimensional sieves for genetic materials, user
defined porous structures for refining, catalytic and fuel cell membranes
are a small sample of potential applications.
Precision mechanical devices and MEMS/NEMS
Immediate applications include precision coatings with
exact dimensions for MEMS, NEMS, IR and UV-VIS mirrors, and engineered
coatings designed for multitasking applications.
Table
1.
Short list of possible products based on this technology.
|
Technology
for the production of 3D anisotropic structures
|
|
I
|
II
|
III
|
IV
|
V
|
VI
|
|
Wear
resistant decorative coatings
|
Wear
resistant conductive thin film coatings
|
Strength enhanced
coatings
|
Quantum
dots arrays
|
Optical
coatings with 3D anisotropy
|
Nano-templates
|
|
Gold
like coatings with imitation of any gold alloy
Silver
like coatings
Platinum
like coatings
Palladium
like coatings
Imitation
of other pressures metal coatings
|
Conductive
pins
Conductive
pads
Interconnections
Inter-
and/or connectors with anisotropic conductivity
|
Cutting
tools
Abrasive
thin film media
Wear
resistant CD disks and others
Wear
resistant optical coatings
|
Nano-dimensional
reverse media
Field
emission nano-tip arrays based on:
A
metal dots
B
carbon nanotubes and diamond like materials
C
diamond
D
semiconductors
Thermostable
quantum dot arrays
|
Reflective
coating for harsh environment
Optical
reversible media for harsh environment
Polarized
reflective films
Interference
filters
|
Nanodimensional
filters
Nano-templates
from nitrides
Nano-templates
from oxide
Nano-templates
from carbides
Nano-templates
from silicides
Nano-templates
from other materials
Nano-electrodes
3D
nano-sculptured multi-components films
|
This technology
is applicable through a wide range of applications and can be readily commissioned
to mass production.
We perceive a production system to look very much like
a standard deposition production facility.
Our interest is in licensing the technology and in providing
technical assistance.
We are very excited about this technology and truly believe it to possess
significant market potential.
If you are interested in this technology or have questions
of any kind, please contact Dr. Yuval Avniel at MicroPowder Solutions,
LLC.
MicroPowder
Solutions, LLC ., 1600 Sherwood Street, Missoula, MT 59802
(406) 550 4647