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Performance
of 50 Completed ATP Projects
Status
Report - Number 2
NIST SP 950-2
Chapter
4 - Electronics, Computer Hardware & Communications
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AstroPower,
Inc.
Manufacturing Technology for
High-Performance Optoelectronic Devices
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| Optoelectronic
devices — from light-emitting diodes (LEDs) and solar cells to
lasers and detectors — are abundant in everyday life. Millions
of LEDs are used in automobile dashboards and consumer electronic
products (clocks, radios, VCRs, CD players, coffee brewers, and microwave
ovens), as well as in commercial and industrial products such as fax
machines, copiers, and printers. |
COMPOSITE
PERFORMANCE SCORE
(Based on a four star rating.)
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A large area
solar grade silicon sheet emerging from a silicon growth reactor which
incorporates new ATP-funded technology. |
LEDs That are Four
Times as Bright
Although LEDs are used in many applications where digital readout is needed,
they have limitations. They do not emit much light, so they cannot be
seen at a distance. If they produced really bright light, LEDs would be
even more widely used than they are already. This ATP project with AstroPower,
a small Delaware company incorporated in 1989, developed a new approach
to production-scale liquid-phase epitaxy (LPE). The company has fabricated
LEDs in a way that significantly increases, by a factor of four, the brightness
of the light they emit.
A New Approach
LPE is a widely used technique that involves melting a semiconductor material
and letting it crystallize on a substrate. AstroPower’s novel enhancement,
the first technical goal of the project, involved the use of a thermal
gradient that promotes the growth of the epitaxial layer laterally much
faster than vertically from the substrate. Company researchers made significant
advances in understanding growth processes for compound semiconductor
materials and in applying LPE to lateral growth over buried reflectors
and other components. The technology can be used for volume production
of low-cost compound semiconductor devices — those made from a compound
of elements, such as gallium arsenide, rather than a single element.
AstroPower’s
second technical goal was to develop the technology to automate the new
LPE growth process in integrated factory-scale fabrication equipment.
Company researchers succeeded in designing and assembling a modular prototype
production growth system that has already significantly shortened production
scale-up times for currently fabricated products, as well as for potential
products under consideration by customers.
Market Developments
Upset Initial Commercialization Plans
Commercialization of the enhanced compound semiconductor devices in high
volumes has not yet happened. An initial goal, to produce high volumes
of red LEDs, has been stymied by market developments. The Japanese have
come to dominate the market for red LEDs, which have become a commodity
product. Although AstroPower has a technical advantage in producing the
devices, the value of this market to the company is quite small, since
the cost of entering the market is too high to make such a venture profitable.
Use
of the Technology for Current Product Lines
Knowledge developed in the ATP-funded project, especially advances in
understanding epitaxy technology, has proven useful across all company
production activities, AstroPower officials say. They report that the
company’s product lines have all grown rapidly in recent years, and
they attribute much of the growth to the ATP project. All of AstroPower’s
compound semiconductor-based
products incorporate epitaxial growth in their fabrication. This includes
their flagship product, the Silicon-Film™ solar cell. Silicon-Film™
is a continuous production process to manufacture crystalline silicon
sheets and layers.
Shortened Production
Scale-Up Times
The success of the ATP-funded project ensures that new and innovative
optoelectronic devices will have significantly shorter production scale-up
times than were possible before the project. The establishment of a technology
that permits low-cost, high-throughput synthesis of compound semiconductor
structures is potentially useful for many optoelectronic device products.
It can be used, for example, in making specialty devices on a job-order
basis using gallium arsenide, gallium arsenide-on-silicon, indium phosphorus,
and a host of other unexplored alloys. These devices are used in the fabrication
of common products like detectors, solar cells, sensors and light-emitting
products. The new technology can also be used in the production of highly
sophisticated devices such as vertical cavity surface emitting lasers
and resonant optical cavity detectors with back reflectors.
AstroPower intends
to incorporate this technology in a number of breakthrough devices that
it can produce in sufficiently large quantities when appropriate market
size has been achieved. Two significant applications are nearing product
introduction. The first is combustion sensors, based on gallium phosphorus
compounds, that can be used for flame control in internal combustion engines
and utility burners. The second is avalanche photodiodes and detectors,
based on indium-gallium-arsenic-antimony and indium-arsenic-antimony-phosphide
compounds, that can be used for light direction and range instruments,
collision avoidance, atmospheric gas measurements, weather prediction,
spectroscopy, blood gas analysis, and noninvasive medical analysis. These
two products are currently in pilot production and are being tested by
NASA, the Air Force, and industrial companies.
Company Growth
At the beginning of the ATP project in 1992, AstroPower had annual product
sales of $1 million. By 1997, sales had grown to $16 million. And in February
1998, AstroPower successfully conducted an initial public offering of
stock, raising $16.7 million.
AstroPower is convinced
that had it not conducted the ATP-funded project, its growth experience
(as measured by product sales) would have been set back by three years,
the length of the ATP project. This belief is based on the use of improved
epitaxial growth technology across all of its product lines, its application
of manufacturing automation processes to all of its manufacturing operations,
and to the overgrowth of semiconductor materials on dissimilar substrates
as well as on mirrors, insulators, and conducting planes. Without the
ATP funds, AstroPower says it would not have carried out the project.
Cross-sectional
photomicrograph of a light emitting diode showing device active layers
and buried mirror overgrowth. |
Potential Large Economywide
Benefits
AstroPower noted at the beginning of its ATP project in 1992 that it expected
in a project like this that products might take as long as 10 years to
move from initial technology development to new product sales. The demonstration
production facility AstroPower developed is capable of producing millions
of LEDs or other LPE-based optoelectronic devices per month. When sufficient
demand for the new products emerges, AstroPower plans to construct an
optoelectronic semiconductor chip-manufacturing facility for new products
made possible by the innovative LPE-growth technology.
Benefits are already
accruing to purchasers of the company’s solar cells, which have higher
quality and cost less than they did before the ATP project. If the company
succeeds in bringing to market additional products that use the new technology,
even more benefits will accrue to its customers. Because of substantial
uncertainty about these events, it is too speculative at this time to
try to predict the magnitude of these future benefits.
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Project
Highlights
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PROJECT:
To develop new crystal growth methods and high-throughput manufacturing
technology for fabricating light detectors and emitters with integrated
reflecting mirrors.
Duration: 7/15/1992 to 7/14/1995
ATP Number: 91-01-0142
FUNDING (in
thousands):
| ATP |
$1,423
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47%
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| Company |
1,580
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53%
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| Total |
$3,003
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ACCOMPLISHMENTS:
The company achieved the goals of the ATP project: developing new
epitaxial growth methods, as well as new processes for plant-scale
industrial production operations. Evidence of the company’s
achievements are that it:
- received
four patents related to the ATP project technology; “Columnar-Grained
Polycrystalline Solar Cell and Process of Manufacture”
(No. 5,336,335: filed 10/9/1992, granted 8/9/1994)
“Hetero-Epitaxial Growth of Non-Lattice Matched Semiconductors”
(No. 5,356,509: filed 10/16/1992, granted 10/18/1994)
“Columnar-Grained Polycrystalline Solar Cell and Process
of Manufacture”
(No. 5,496,416: filed 8/5/1994, granted 3/5/1996)
“Semiconductor Device Structures Incorporating 'Buried' Mirrors
and/or 'Buried' Metal Electrodes” (No. 5,828,088: filed 9/5/1996,
granted 10/27/1998);
- demonstrated
the application of the new epitaxial production technology to
optoelectronic device structures that have integrated reflecting
mirrors for enhancing light output (an ultrabright light-emitting
diode (LED) with buried reflectors), achieving a fourfold increase
in brightness;
- completed
scale-up of liquid-phase epitaxy (LPE)-growth technology to a
high-throughput, production-scale process;
- significantly
shortened production scale-up times for specific products, compared
with previous manufacturing processes;
- constructed
a demonstration production facility to implement the technology;
and
- conducted
an initial public offering of stock in February 1998, raising
$16.7 million.
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CITATIONS
BY OTHERS OF PROJECT’S PATENTS: See Figure
4.3.
COMMERCIALIZATION
STATUS:
Direct commercialization of ultrabright red LEDs, a proposed initial
goal of the project, did not occur, mainly due to economic and market
developments. Knowledge of new crystal growth methods acquired during
this project contributed, however, to the enhancement of fabrication
methods for the company’s Silicon-Film™ solar cell and
for other compound semiconductor devices.
OUTLOOK:
AstroPower has applied the ATP-funded crystal growth technology
to its current manufacturing processes, improving productivity and
lowering costs. It also plans to use the technology for several
breakthrough devices when appropriate market size has been achieved;
if such markets develop substantially, the outlook is promising.
Two significant products that are nearing introduction are combustion
sensors based on gallium-phosphorus compounds, and avalanche photodiodes
and detectors based on indium-gallium-arsenic-antimony compounds.
Composite
Performance Score:
COMPANY:
AstroPower, Inc.
Solar Park, 461 Wyoming Road
Newark, DE 19716-2000
Contact:
James B. McNeely
Phone: (302) 366-0400
Number of Employees: 86 at project start; 160 at the end
of 1997
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Return to Table
of Contents or go to next section.
Date created: April
2002
Last updated:
April 12, 2005
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