5 Non-LED Uses of Sapphire

Rubicon Technology may be best known as the worldwide market leader in sapphire for LEDs, but the company’s sapphire is being used in applications far beyond the lighting industry.

From semiconductor equipment components to camera lens covers, there are many intriguing uses for optical and non-wafer sapphire. Here’s a peek at five non-LED usages for Rubicon’s synthetic sapphire.

Rubicon1. Semiconductor Equipment  Components

More than 40 different semiconductor equipment components are made of sapphire. Due to its ability to withstand very high temperatures, extreme environment processing and harsh chemicals like fluorine plasma and many acids, sapphire is ideal for equipment such as plasma tubes, heater plates, lift pins and chamber windows.

2. Medical Component

Sapphire products are used in a variety of medical applications, including dental braces, surgical blades, laser delivery windows, arthroscopy lenses and skull pins. When compared with traditional metal alternatives, medical sapphire components provide advantages of optical transmission, transparency for both aesthetic and performance improvements, high durability and precision, and also can be utilized for procedures requiring active imaging as sapphire does not impact imaging processes like metal.

3. Infrared (IR) Windows

Sapphire windows of optical quality are already being used for military sensing applications on aircrafts and missiles. In fact, sapphire IR windows are now beginning to be used on private, commercial and cargo aircraft to assist with landing in inclement weather.

4. Wafer Carriers

Sapphire is so durable that it is actually used to support other brittle wafers that are being processed, such as gallium arsenide and silicon carbide. These brittle wafers are mounted to sapphire so they do not break or get damaged during transit.

5. Durable Lenses and Windows

One of the largest optical applications for sapphire is in the form of lenses and windows. Due to its hardness and wide range of transmission from UV to Visible to IR wavelengths, sapphire lenses and windows are ideal for use in applications where there is a possibility of impact, scratching, high temperatures, chemical interaction or other harsh conditions. These lenses and windows are used in a wide variety of applications, such as camera lenses, military rifle scopes and as windows for sensors and laser transmission.

We are just scratching the surface when it comes to optical and non-wafer uses for sapphire. As research continues and new applications are discovered, you will see sapphire included in different types of products. Who knows, you may soon be seeing sapphire used for the armored windshields of military vehicles or even in hip replacements!

The challenges of growing the world’s largest sapphire slab

Can optical quality sapphire be grown in a different way to create a large, thick window to protect equipment on the belly of an aircraft?

This is the question that members of the Rubicon Technology design team were asked when the United States Air Force Research Lab (AFRL) called upon them about three years ago to develop a new growth platform that could produce very large polished sapphire infrared (IR) windows.

In the past, these dimensions were met by piecing together several smaller sapphire windows, with less-than-desired performance.

Despite high interest from the defense and aerospace industries, no method for producing sapphire for optical-grade windows of such great size and thickness existed at the time. Sapphire had been limited to smaller sizes and shapes using traditional growth methods. Rubicon studied the problem and agreed that it could be done. In 2012, the Air Force Research Laboratory granted Rubicon a three-year research contract to develop this product.

With several “firsts” already under its belt, such as having been the first to commercialize 6-inch and 8-inch wafers for the LED industry and the first to produce large-diameter patterned sapphire substrates, Rubicon has now successfully become the first to grow a 36 x 18 x 2-inch sapphire slab.

Drawing upon its strong history of scaling up sapphire growth processes, Rubicon successfully produced large sapphire blanks by highly modifying the Horizontal Directional Solidification (HDS) process and developing LANCE. Unlike the ES2 method, which produces high-quality sapphire crystals in the shape of roughly cylindrical boules, the HDS method produces sapphire plates that are advantageous for shaping into large windows.

Scaling up to larger crystal sizes while maintaining crystal quality was, of course, the real test and involved development of a new type of furnace.

Devising how to maintain crystal quality at such a large size proved to be experimental and time-intensive for the designers. By combining multiple platforms, materials and heater types, Rubicon ultimately demonstrated the ability to pull a horizontal boat through a heater surrounded by thermal insulation to achieve the desired thick slab while maintaining its high quality.

Over the past two years, the design team has continued to tweak and perfect the LANCE process, keeping the ultimate goal in mind of producing a sapphire slab with the cut measurements of 36 x 18 x 2 inches. The project is on track to produce optical quality sapphire at this immense size.

Looking to the future, this monolithic sheet is a hugely innovative advance that will provide a large, seamless optical field for military sensing applications and beyond.

For more information on the LANCE project, visit http://www.rubicontechnology.com/research-development/project-lance-very-large-sapphire-windows.

Case Number 88ABW-2015-1571

Sapphire Industry Watch – April 3

  • International Youth Culture Centre glows with colorful LED lighting – Gizmag: With 700,000 high-efficiency LED nodes, LED linear lighting and LED flood lighting, the International Youth Culture Centre in Nanjing, China is a colorful addition to the city’s skyline. The LED system’s palette of 16 million colors beautifully illuminates the development, while being more energy efficient than traditional LED lights. The system, which was designed by Philips, is reported to save up to 60 percent in electricity used compared to normal LED lights.
  • Seattle Mariners first team to use LED lights, last 97,000 more hours – UPI: Safeco Field, the home of the Seattle Mariners, is the first Major League Baseball stadium to fully illuminate its playing field with LED lights. In addition to reducing glares and shadows on the field, the LED lights turn on instantly and have reduced energy consumption for field lighting by up to 70 percent.
  • Rubicon appoints GTAT’s former VP of crystal growth systems development as CTO – Semiconductor Today: Dr. Christine Richardson has been appointed as Chief Technology Officer of Rubicon Technology. Formerly the Vice President of Crystal Growth Systems Development & Engineering at GT Advanced Technologies, Richardson will take responsibility for the ongoing development of Rubicon’s technology platforms and also lead R&D activities.
  • Solar flower trees to power up alternative lighting solutions – The Times of India: The Kerala State Electricity Board (KSEB) has installed two solar flower trees in front of its headquarters as part of the state’s initiative to promote alternative lighting solutions in public spaces. The geometrically-cut flower-shaped solar panels generate power throughout the day and, if it’s sunny enough, LED lights attached to the petals can remain lit continuously for up to 12 hours.

Sapphire Industry Watch – March 27

  • Disco Dog smartphone-controlled LED vest makes your dog a party animal – Slashgear: New York creative firm PARTY has invented a LED covered vest for dogs – dubbed Disco Dog – that can be controlled by a smartphone via Bluetooth to display animated patterns of light. In addition to making a dog the life of the party, the vest has additional safety features, such as the option to automatically update the vest with a scrolling message of “Lost Dog” if the pup runs out of range.
  • Aerial fire truck add-ons to boost function – Fire Chief: LED technology is being used on aerial fire trucks to improve visibility and scene safety. Manufacturers are installing LED rope lights on both sides of ladders to better illuminate the path to the building, making it safer for personnel climbing the ladder and easier for the turntable operator to see where the ladder is during low visibility conditions.
  • This Millennium Falcon paper model looks real enough to fly – CNET: After four years of tedious assembly, Polish artist and self-proclaimed “Star Wars” fan Bernard Szukiel debuted his paper model of Hans Solo’s legendary ship, The Millennium Falcon, at the “Star Force” exhibition in Torun, Poland earlier this month. Measuring at 38 inches, the model was built using only paper, thin cardboard, a few wires, clamps, optical fibers and LED lights. The LEDs allow the model to light up like in the original movie.
  • Rubicon showcasing large-diameter patterned sapphire substrates for LED market – Semiconductor Today: Rubicon Technology showcased its large-diameter patterned sapphire substrates as well as its line of 4” and 6” polished sapphire wafers for the LED industry at LED Taiwan 2015. With an edge exclusion zone as small as 1mm, Rubicon offers LED chip makers more usable area to maximize the number of chips per wafer. LED Taiwan 2015 was held in Taipei from March 25-28.

What is the strongest natural material on Earth?

Materials like sapphire, diamond, Kevlar and even spider silk are all well-known for their incredible strength.

Now there’s a new entrant into the conversation, and forgive them for being a bit late—they are snails, after all.

A recent scientific study published in the Journal of the Royal Society Interface has declared limpet teeth as the new official strongest natural material on earth. For those not up to date on gastropods, limpets are small sea snails that live in both fresh and salt water and use their super strong teeth to scrape food off rocks.

Limpets

We’re talking tensile strength here, not hardness.  Hardness and tensile strength are fairly different. A simplification would be that hardness is a resistance to scratching while tensile strength reflects a resistance to breaking.

What is it about limpet teeth that make them so strong?

The tiny teeth are made of very thin, tightly-packed fibers that contain the hard mineral goethite. At 1/100th the diameter of a human hair, the ultra-thin fibers create an almost flawless weave that trumps even man-made carbon fibers.

As the author of the study Professor Asa Barber of The University of Portsmouth put it:

“Generally a big structure has lots of flaws and can break more easily than a smaller structure, which has fewer flaws and is stronger. The problem is that most structures have to be fairly big so they’re weaker than we would like. Limpet teeth break this rule as their strength is the same no matter what the size.”

To gauge the fibers’ tensile strength, Professor Barber attached each end of a small piece of the material to a lever and pulled on the sample until it broke. He found that the material had a strength of 5 gigapascals, which is five times the strength of spider silk and even beats out Kevlar. The tensile strength in this case comes primarily from the structure at a macroscopic level, not the same as crystal structure, which is molecular.

In the future, Professor Barber hopes to see the fibrous structures of limpet teeth studied and used by engineers for high-performance applications, such as Formula One race cars and boat hulls.

Until then, the team at Rubicon gives limpets a tip of the hat for having teeth made of the strongest natural material on Earth.

Stephen Colbert

Sapphire Industry Watch – March 13

  • Rubicon CEO Discusses Applications for Sapphire – NBC 5 Chicago: Bill Weissman, CEO of Rubicon Technology, discusses current uses of sapphire in every day applications such as LED lighting and mobile applications, as well as more unique uses like invisible braces and high-end razor blades. As Rubicon continues to experiment with ways to bring sapphire manufacturing costs down, there is enormous potential for new and exciting applications of sapphire in the future.
  • Are LEDs About to Take Over the World? – The Huffington Post UK: Although the first LED light was produced in 1962, it wasn’t until recently that increased sustainability efforts and lowering costs encouraged the widespread adoption of LEDs. From the Empire State Building’s lighting renovation to NASA’s development of LED facials, it is clear we are living in the age of the LED.
  • Auckland’s bridge lit up by 51 thousand bulbs – stuff.co.nz:  In celebration of the city of Auckland’s 175th anniversary, New Zealand’s iconic Auckland Harbour Bridge is being transformed into an interactive art, music and light show for the next six weeks. More than 51,000 LED light bulbs have been synced to music chosen by the public and performances can be watched in-person, and also via live stream on mobile phones and laptops.
  • San Diego School District Uses Prop 39 Funds for Energy Savings – Energy Manager Today: Thanks to $850,000 in funding from Proposition 39, the California Clean Energy Jobs Act, the Del Mar Union School District in San Diego will be replacing current light fixtures with longer-lasting LED light fixtures with occupancy sensors and dimming controls. The school district will also receive a rebate for the LED installations from San Diego Gas & Electric.

Sapphire Industry Watch – February 6

  • S.F. replacing old streetlights with cheaper, better LED bulbs – SF Gate: As part of an $11 million upgrade program, San Francisco is beginning to replace 18,500 old high-pressure sodium street lights with new LED lights. The LEDs will not only improve lighting and reduce maintenance costs, but also move “the innovation capital of the world” into a “smart” electrical grid.
  • Canada dims the light on the incandescent light bulb – The Globe and Mail: As of January 1, 2015, 60- and 40-watt incandescent light bulbs can no longer be manufactured or imported into Canada. The decision was made by the federal government in an effort to cut energy consumption and encourage Canadians to switch to LEDs. The ban is an extension of the ban on 75- and 100-watt bulbs that came into effect in 2014.
  • Rubicon Technology Appoints Hap Hewes as Senior Vice President, Optical – Yahoo! Finance: Rubicon Technology announced the appointment of Hap Hewes as Senior Vice President, Optical. He will lead marketing and business development activity for sapphire products in the aerospace, optical, consumer electronics and industrial markets. After departing from Rubicon in 2009, Hewes has returned to the company to bring this wide range of exciting new products to market and to lead the company’s traditional optical components business.
  • LED system will set the mood inside new Vikings stadium – Star Tribune: The new Minnesota Vikings stadium in Minneapolis will be the first football stadium in the United States to install LED lighting during initial construction. The new lights are projected to consume 75 percent less energy than traditional lighting and Vikings officials say they have kept an environmentally friendly focus during the project’s planning and construction phases.

Sapphire Industry Watch – January 30

  • Public servants to take power to India’s slums in international move – Canberra Times: Pollinate Energy is a social enterprise with a mission to improve the lives of India’s urban poor by providing access to sustainable technologies like solar energy and LED lights. Co-founded in 2012 by a Canberra woman, the organization has already helped more than 25,000 people in Bangalore switch to solar LED lighting in their homes.
  • The First Super Bowl Played Under LEDs will use 75 Percent Less Power– Gizmodo: Sunday’s Super Bowl between the New England Patriots and the Seattle Seahawks at the University of Phoenix Stadium in Glendale, Arizona will be the first Super Bowl played entirely under LED lights. The switch from metal halide fixtures to high-performance LED lights will reduce overall energy consumption by 75 percent.
  • LEDs cast new light on auto design – The Detroit News: As the price of LEDs continues to decline, the technology is becoming standard on many headlamps and taillights of mainstream vehicles. Once found only on luxury vehicles, nearly all of the models showcased at the 2015 North American International Auto Show incorporated LED lighting.
  • Rubicon Technology Will Report Results of Fourth Quarter Operations on February 12, 2015 – MarketWatch: Rubicon Technology will report financial results for the fourth quarter, which ended on December 31, 2014, after the market closes on February 12, 2015. Management will host a conference call at 5:00 p.m. EST on February 12 in conjunction with the earnings release to review the financial results and an audio replay of the call will be available approximately one hour after the conclusion of the call.

Sapphire Industry Watch – December 19

  • Rubicon’s interim president & CEO made permanent; VP – financial operations becomes CFO – Semiconductor Today: Rubicon Technology announced that its Board of Directors has appointed William Weissman to the permanent position of President and CEO. Weisman has been Interim CEO and President since September 17, 2014 and Chief Financial Officer since 2007. He has also been appointed a member of the Board of Directors.
  • Why LEDs Are Conquering Lighting – Popular Science: As the cost of LEDs continues to plummet and stricter efficiency standards are enforced, we are reaching a tipping point when it comes to LED conversion. LEDs are quickly becoming the preferred lighting source for a variety of applications, from home lighting to street lights.  Because they’re so efficient and highly programmable, LED adoption will continue to rise in the foreseeable future.
  • Christmas Lights Can Be Seen From Space By NASA Satellites– Huffington Post: The effect of holiday lights in cities and suburbs around the world is so powerful that the difference from normal lighting conditions can be detected from space. NASA satellite images show certain cities shine between 20 and 30 percent brighter during the holiday season and in the near future, satellites may even be able to differentiate between traditional lights and LEDs.
  • Virginia Beach switching to LED lights for roadways – PilotOnline.com: Virginia Beach will begin installing LED lighting technology to all new roads moving forward, with 180 LED street lights being installed on the newly expanded Princess Anne Road in January. Unlike the old-style lamps which glowed yellowish-orange, the new flat fixtures will illuminate the street with white light. The city expects to save hundreds of thousands of dollars by switching to LED lights.

Large Diameter Patterned Sapphire Substrates Explained

Rubicon Technology offers large diameter PSS in a range range of shapes including cone, dome and pyramid as well as custom.

Rubicon Technology offers large diameter PSS in a range of shapes including cone, dome and pyramid and range of orientations.

While LED chip manufacturers have been using patterned sapphire substrates (PSS) for years, there’s growing interest in large diameter PSS.  Recently, Rubicon Technology announced the commercial availability of large diameter PSS.  During their latest earnings call, they indicated that they’ve received interest from 7 major LED chip manufacturers for 4- and 6-inch large diameter PSS.  Why the interest from LED chip manufacturers?

First, PSS helps improve epitaxial growth by promoting growth of the GaN in parallel to the substrate surface. This also helps reduce the number of dislocations, called the dislocation density, which can degrade performance of an LED.  Secondly, patterning can help extract as much as 30 percent more light from an LED.  This is particularly advantageous for high brightness LEDs (HB LEDs) that are used in LED lighting applications.

Second, the evolution of patterning large diameter substrates brings economical advantages to LED chip manufacturers, especially those anticipating demand from the LED lighting market.  Large diameter sapphire wafers help LED chip manufacturers cut costs by enabling more throughput for each run of the MOCVD reactor.  This helps chip manufacturers make better use of the reactor “real estate” and decreases the cost per unit of area processed because of the curvature of the larger wafer.  The outer curvature of a 6-inch wafer is less, enabling greater use of the surface area than the tighter curvature of a 2-inch wafer resulting in less edge loss.  Larger diameter wafers also provide post-MOCVD efficiencies.  Depending on the type of MOCVD reactor used, LED chip manufacturers using six-inch wafer platforms may achieve up to 48% greater usable area per reactor run compared with two-inch wafers.  These efficiency gains become very compelling when manufacturers want to ramp up LED chip production to support greater volumes of LEDs for light bulbs.

Finally, LED chip manufacturers have been buying smaller 2-inch and 4-inch PSS from outside suppliers for years.  The next step in the evolution in the market is the migration to large diameter PSS for the reasons we mention above.  While some LED chip manufacturers will have specialized patterning needs and the resources to keep the work in-house, others will not.  Some LED chip manufacturers may not have the expertise and equipment to move to large diameter PSS, so having a ready, trusted supplier will prove handy.

For Further Reading

ClearlySapphire, LED Lighting Spotlight: Patterned Sapphire Substrates http://blog.clearlysapphire.com/?p=390

Semiconductor Today, Patterned sapphire for nitride enhancements, http://www.semiconductor-today.com/features/SemiconductorToday_SeptOct_PatternedSapphire.pdf

Compound Semiconductor, New Wet Process For LEDs On Patterned Sapphire Boosts Efficiency, http://www.compoundsemiconductor.net/csc/news-details.php?cat=news&id=19734296

Compound Semiconductor, Rubicon Orders Multiple Profilers For Sapphire Production, http://www.compoundsemiconductor.net/csc/news-details.php?cat=news&id=19735318

Clearlysapphire.com, Larger Wafers, Larger Yield – The Numbers Behind Large Diameter Sapphire Wafers and Yield, http://blog.clearlysapphire.com/?p=435