Sapphire Industry Watch – May 8

  • The Hidden Perils of Energy Efficient Fluorescent Lighting – Sourceable: Fluorescent lamps have long been seen as a source of energy efficient lighting, but they pose a threat to the environment and human health as a result of their mercury content. Besides being greener in nature, LED light bulbs are devoid of mercury, making them the preferred alternative to fluorescent lamps when it comes to energy efficient lighting.
  • With LED Lights, Automakers Reveal All the Road We Cannot See – New York Times: Thanks to LEDs, automotive lighting is undergoing a quiet revolution that is leading to new vehicle designs and providing enhanced nighttime safety. By combining LED lamps with cameras, a vehicle’s headlights can continuously alter their light patterns to exactly fit road conditions.
  • Green Focused People Power LEDs – The Asian Age: India’s LED light industry is continuing to grow thanks to public awareness and government energy conservation initiatives. According to recent data from the Electric Lamp and Component Manufacturers Association of India, LED lights are likely to account for about 60 percent of the total lighting industry by 2020.
  • Implications for LEDs of The Shift to Large-Diameter Sapphire Wafers – Semiconductor Today (Pgs. 68-71): Rubicon Technology’s senior VP of operations, Faisal Nabulsi, explains the changes in the sapphire wafer market over the past two years, and how large diameter and patterned sapphire substrates are impacting LED manufacturing.

Sapphire Industry Watch – February 20

  • Glasshouse LEDs save greenhouse gasses – Electronics Weekly: As artificial lighting is increasingly used to extend the growing day and growing season inside greenhouses, UK plant researchers are looking into using LED lights to grow plants with less energy. While it is not necessarily the effectiveness of LEDs that is the advantage to growing plans indoors, the ability to save power by only delivering wavelengths useful to plants is highly effective for managing the growth process.
  • LED revolution unfolds in Guntur – The Hindu: Since the Domestic Efficient Lighting Programme (DELP) was launched in October, residents and businesses in the Anantpur, Guntur, Srikakulam and West Godavari districts have begun making the switch from incandescent light bulbs over to LEDs as part of a nationwide effort to conserve energy and money. In a span of just three months, DELP has already covered more than 80 percent of consumers in the district.
  • Rubicon’s Q4 Revenue Up 11 Percent on Q3 – Compound Semiconductor: Last week, Rubicon Technology reported financial results for its fourth quarter, which ended on December 31, 2014. The company reporter Q4 revenue of $8.9 million, an 11 percent increase from the previous quarter. Demand for the company’s two-inch sapphire cores increased considerably in the period.
  • LED lights to save $50K annually for Bridge Authority – Poughkeepsie Journal: The New York State Bridge Authority has announced a new project to improve lighting around the Mid-Hudson Bridge through the installation of LED lights. The project, which will generate more than $53,000 in annual savings, calls for the installation of 174 LED lights. The project will cost $57,069 and include 120 street lights, 22 high mast lights and 32 tower lights.

LEDs Shine Brighter with Patterned Sapphire Substrates (PSS)

LEDs are being adopted across a wide range of products, from general lighting, automobile headlights and traffic signals, to backlighting for consumer devices like HDTVs, smartphones and tablets.

Evidence of that, LED manufacturers racing to improve luminous output and reduce cost in order to win greater market share.

The July/August 2014 issue of LEDs Magazine features Rubicon Technology’s Donggeun Ko, Jacob Yoon and Jangho Seo, who discuss how applying patterns on an LED substrate or wafer can significantly help increase LED light extraction.

In fact, it’s reported that patterning can improve the extraction of light by as much as 30 percent.

The article in LEDs Magazine outlines key considerations for effective PSS design to maximize light output of LED chips, such as reducing defect density and total internal reflection losses.

The full article in LEDs Magazine can be viewed here.

It’s also worth mentioning …

Today, sapphire wafer manufacturers have begun to put patterns on sapphire wafers in partnership with the LED chip manufacturers, with most sapphire manufacturers concentrating on small diameter patterning in the 2-to-4 in. range.

Manufacturers of large diameter wafers, such as Rubicon Technology, are developing PSS for large wafers (up to 8 in. diameters) and differentiating their offerings with better quality control and an unmatched end-to-end manufacturing process.

Interested in learning more? Check out additional info about patterned sapphire substrates here.

9 Things You Didn’t Know About Sapphire

It’s no surprise that there’s been recent speculation about Apple’s use of sapphire in the display screen of the iPhone 6. Regardless of whether or not that happens, sapphire is a modern marvel that has interesting applications far beyond the smartphone market.

Rubicon Technology, Inc., has put together a list of things you might not know about sapphire, from the characteristics that make it so versatile to its potential future applications.

Let’s take a look at why sapphire offers so much promise.

  1. Sapphire used for practical purposes, outside of jewelry, is synthetically grown, and then cut and polished, since clear, colorless sapphire gemstones almost never occur in nature. Synthetic sapphire has a similar composition to the gemstone, but is grown under controlled conditions to prevent  internal stresses that can weaken the crystal. Check out a video on how sapphire is made, featured on the TV show “How Do They Do It.”
  1. Speaking of heat, sapphire has a melting temperature of 2030 degrees Celsius — which is 20x the boiling point of water.
  1. Sapphire is the second hardest material on earth behind diamond and is so strong that it’s been effectively used as bulletproof “glass.”
  1. Apple isn’t the first smartphone company to utilize a sapphire face plate. In fact, luxury phone maker Vertu has been using sapphire screens for 15 years. You can also find sapphire onlens covers of certain smartphone cameras and the fingerprint scanner/home button on the iPhone 5S.
  1. Sapphire is the primary material used as the foundation for LED chips, which can be found all around you in products like traffic lights, light bulbs, HDTVs, tablets, computer monitors, gaming systems and mobile phones. The majority of the commercial sapphire produced today goes into LEDs.
  1. In the future, sapphire could be used for a variety of medical purposes, including artificial joint replacements, given that it’s not only biocompatible so it won’t react with the body but also harder and more durable than ceramics and stainless steel.
  1. You may know that high-end watches have sapphire faces given the crystals’ exceptional clarity and scratch-resistant surfaces. Those same reasons are why sapphire is used in the optic heads of missiles.
  1. Sapphire is used to cover barcode scanners, like the ones you see at the grocery store.
  1. The potential uses for sapphire are truly unlimited! Just imagine one day having ultra-strong wine glasses for those of us with the propensity for breaking them.

Substrate Update: It’s All About Patterning & Large Diameter Wafers

yole_developpement_logoMarket research firm Yole Developpement recently published a new report on front-end manufacturing trends for LEDs. Their latest report gives us some very good news about the sapphire market. Semiconductor Today reported on Yole’s analysis. Here are some big take-aways:

  • There is increased demand for larger-diameter sapphire wafers, with big players (such as LG, Sharp or Osram) moving to 6” wafers and Taiwanese players moving to 4” wafers.
  • LED chip makers demand more patterned sapphire substrates (PSS). PSS are now mainstream in the market with an 87% share as of Q1 2014.
  • While some companies (such as Soraa and Toshiba) have begun mass production of gallium nitride-on-silicon (GaN-on-Si) and GaN-on-GaN LEDs, market penetration of these alternative substrates will depend on future improvements in terms of performance and cost.  Without these improvements, alternative substrates will not be able to fully compete with sapphire-based LEDs.

What does this mean for sapphire makers? LED chip manufacturers are looking to gain production efficiencies, lower costs, and increase performance for their LEDs.  As the adoption for LED lighting increases, they need to make more and better performing LEDs. Large diameter sapphire wafers enable more throughput for each run of the MOCVD reactor, making better use of the reactor “real estate” and decreasing the cost per unit of area processed. 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 as compared to two-inch wafers.

What does PSS offer? First, PSS helps improve epitaxial growth by promoting growth of the GaN in parallel to the substrate surface. This 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.

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. Already a pioneer in the development of large diameter sapphire substrates, Rubicon Technology has developed capabilities for large diameter PSS making it possible to manufacture 6-inch and even 8-inch PSS. Rubicon is already gaining traction in the PSS market.  The company recently reported in their Q1 2014 earnings call that they received their first order for PSS and have samples out to more than a dozen LED chip manufacturers.

For more information about the report from Yole, visit http://www.i-micronews.com/reports/LED-Front-End-Manufacturing-Trends-report/14/433

For Further Reading

Semiconductor Today, Substrates shaping trends in LED front-end manufacturing, http://www.semiconductor-today.com/news_items/2014/APR/YOLE_300414.shtml

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

Clearlysapphire.com, Large Diameter Patterned Sapphire Substrates Explained, http://blog.clearlysapphire.com/?p=582

Clearlysapphire.com, Sapphire Substrates for LED: The Big Move Toward 6″ Has Already Started, http://blog.clearlysapphire.com/?p=37

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

Rubicon Announces Large Diameter Patterned Sapphire Substrates

PSS with dome shape

PSS with dome shape

 

This week, Rubicon Technology announced the launch of the first commercial line of large diameter patterned sapphire substrates (PSS) in four-inch through eight-inch diameters.  The new product line provides LED chip manufacturers with a ready-made source of large diameter PSS to serve the needs of the rapidly growing LED general lighting industry.

This is doubly important since patterning helps improve both epitaxial growth and light extraction for each chip and enhances a chipmaker’s throughput and efficiency.  Rubicon announced that they have fully customizable sub-micron patterning capability with tight dimensional tolerances, within ±0.1 µm.  Rubicon offers LED chip manufacturers more usable area to maximize the number of chips per wafer due to an edge exclusion zone as small as 1 mm.  Rubicon’s patterning is available in a range of shapes including cone, dome and pyramid, and in a range of orientations.  Further customization of geometry, pattern and orientation is available too.  You can find a brochure about it on Rubicon’s web site here.

Rubicon’s president and CEO Raja Parvez pointed out the importance of large diameter patterned sapphire substrates in a news release.  “As LED-based general lighting gains worldwide adoption, large-diameter patterned sapphire substrates will become necessary to meet the demands of the rapidly growing lighting market.”

Parvez added that the company developed an unmatched technology platform that is vertically integrated from raw material through crystal growth, large diameter polished wafers, and now custom PSS in 4”, 6” and 8” diameters.  According to Parvez, vertical integration enables Rubicon to produce progressively larger sapphire products while providing customers with exceptional quality, cost control, reliability, and consistency.

For Further Reading

Rubicon Technology, Rubicon Technology Launches First Commercial Line of Large Diameter Patterned Sapphire Substrates for the LED Industry, http://bit.ly/1itVMHq

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

 

Sapphire – Quality Matters, Part 2: Transmission Quality

Recently, Novus Light Today published an article by Dr. Jonathan Levine, Director of Technical Business Development at Rubicon Technology, about sapphire quality.  His article shares a thorough review of the measures of sapphire quality for optical-grade applications.  Last week, we looked at the first two metrics, chemical analysis and X-ray rocking curves.  This week, we’ll look at transmission quality.

Levine writes that the quality of a sapphire is determined by how closely the grown crystal matches the ideal structure with respect to the arrangement of atoms within the lattice, dislocations, defects, and stress.  Root causes for these problems often originate from insufficient purity of the starting material and the growth process itself.

Sapphire exhibits excellent transmission in the ultraviolet (UV) to the mid-infrared (IR) range (~200 – 5000 nm).   According to Levine, conditions within the sapphire growth furnace can induce subtle interactions between the molten sapphire and the growth environment.  These interactions can produce bubbles, dislocations and other stresses that could impact optical performance.   Levine says that carefully controlling the growth environment produces sapphire that maintains excellent transmission at 200 nm through the mid-IR wavelengths.  He illustrates the impact of furnace interactions by comparing Rubicon’s ES-2 sapphire with another commercial sapphire maker’s crystal produced using a different growth method in the figure below.  From the image in the post, you can see a sharp absorption peak at 200 nm for sapphire produced by the commercial maker that is absent in sapphire grown by Rubicon.

Optical transmission of sapphire depicting a sharp absorption peak at 200 nm for sapphire produced by a commercial producer that is absent in sapphire grown by Rubicon.  Inset: Optical transmission for Rubicon sapphire from the visible to mid-IR range approaching 90% due to the high quality of the material.

Optical transmission of sapphire depicting a sharp absorption peak at 200 nm for sapphire produced by a commercial producer that is absent in sapphire grown by Rubicon. Inset: Optical transmission for Rubicon sapphire from the visible to mid-IR range approaching 90% due to the high quality of the material.

For Further Reading

Novus Light Today, Optical-Grade Sapphire, Where Quality Matters, http://www.novuslight.com/optical-grade-sapphire-where-quality-matters_N1596.html#sthash.giGipxT1.dpuf

Sapphire Quality Matters: Part 1

Sapphire is an extremely versatile material with a growing list of applications in a wide range of industries.  Sapphire suits optical applications because of its scratch resistance and its transmission characteristics.  You’ll find sapphire components such as lenses and windows in medical equipment, lasers, satellites, aircraft, flame detectors, smart phones, cameras and watches.  Recent advances in sapphire crystal growth technology and fabrication have improved the performance, purity, and availability of sapphire for all types of applications.

Recently, Novus Light Today published an article by Dr. Jonathan Levine, Director of Technical Business Development at Rubicon Technology, about sapphire quality.  His article gives a thorough review of the measures of sapphire quality for optical applications.  Levine writes that the quality of a sapphire is determined by how closely the grown crystal matches the ideal structure with respect to the arrangement of atoms within the lattice, dislocations, defects, and stress.  Root causes for these problems often originate from insufficient purity of the starting material and the growth process itself.

The effects of these variables in the final product are commonly quantified by three metrics: chemical analysis, X-ray rocking curves, and optical transmission.  Additionally, the observance of bubbles in the crystal provides a baseline from which crystal quality is determined because bubbles serve as scattering centers for any light transmitted through a sapphire optic, thus reducing its performance.

This week, we look at the first two metrics, chemical analysis and X-ray rocking curves.

Powdered aluminum oxide

Powdered aluminum oxide

 

 

 

 

 

 

Purity of the crystal is highly important.  According to Levine, the presence of certain elements can vary drastically between suppliers, and sapphire manufacturers must exercise proper quality control.  For example, titanium (Ti) and chromium (Cr) impurities can result in pink crystals.  In nature, these impurities lead to rubies and other variations of sapphire depending on the impurity.  Levine says trace amounts of these elements must be kept below 1 ppm.  Levine includes a graphic about other elements that can cause issues including silicon (Si), potassium (K), chlorine (Cl), iron (Fe), lithium (Li), and sodium (Na).  The data was collected using glow discharge mass spectroscopy (GDMS).

Typically, a company can buy two types of raw material for crystal growth that can have impurities.  Levine says it can be purified alumina powder and/or Verneuil sapphire.  Rubicon has developed a new in-house purification process that converts the raw powder into densified pellets for crystal growth without an increase in cycle time or decrease in crystal yield. This process enables Rubicon to eliminate impurities in the alumina power that they use to make crystal.

Levine includes another useful metric for analyzing sapphire, rocking curve data obtained via X-ray diffraction.  A rocking curve helps measure various stresses in a crystal.  Levine says the width of the resulting peak is highly sensitive to strain and defects within the crystal.  A narrow peak, indicated by its full width at half maximum (FWHM) measured in arcseconds, signifies a high quality crystal free of low-angle grain boundaries and lattice strain.  A standard narrow rocking curve for Rubicon’s ES2 sapphire windows is shown below.

Sample rocking curve data from Rubicon ES2 sapphire.

Sample rocking curve data from Rubicon ES2 sapphire.

 

 

 

 

 

 

 

 

What can introduce a poor rocking curve?  Levine says that high thermal gradients, fast growth rates, and impurities contributed by the surrounding insulation can introduce defects and stress into the crystal that subsequently yield poor results in rocking curve data.  He adds that accurately controlling the temperature gradient and maintaining a stable growth interface throughout the entire process can help make higher quality sapphire.

For Further Reading

Novus Light Today, Optical-Grade Sapphire, Where Quality Matters, http://www.novuslight.com/optical-grade-sapphire-where-quality-matters_N1596.html#sthash.giGipxT1.dpuf

How Do They Do It? From Sapphire to LED Infographic

You’ve heard a lot about LEDs, but did you know that a tiny piece of sapphire – the pure, colorless industrial variety, not the blue gemstone – is in more than 80% of LEDs? Sapphire is the foundation for the LED chip, just as silicon is for a computer chip.  Rubicon Technology has put together an infographic that describes the sapphire manufacturing process and where sapphire is found in an LED. The bottom of the infographic features examples of products that feature LEDs for lighting. Click on the infographic below to see it larger.

Infographic for Post

 

 

 

 

 

Link to: http://www.rubicontechnology.com/sites/default/files/From%20Sapphire%20to%20LED%20Infographic.pdf