Let There Be Light
A quiet revolution is underway. Over the next 5-10 years, inorganic semiconductor based solid state lighting technology is expected to outperform first incandescent, and then fluorescent and high intensity lighting. Solid state lighting through light-emitting diodes (SSL-LED) is the use of solid state, inorganic semiconductor light-emitting diodes to produce white light for illumination.
SSL-LED
Like semiconductor transistors, which displaced vacuum tubes for computation, SSL-LED is a disruptive technology. It has the potential to displace vacuum or gas tubes (incandescent and fluorescent lamps) for general white lighting. Furthermore, other colors based on the same SSL-LED technology have become brighter and ever long lasting, consuming orders of magnitude lower than traditional lighting. The global LED market has already reached the $2 billion per year mark and is expected to reach the $3B mark by early 2006.
Machine vision and architectural lighting are the niche markets for this technology at the moment, representing only 8% of the market. By far, the handheld devices such as cell phones PDA’s and other electronics lead with 40% of the market SS-LEDs. LED’s have also found their way to the hottest electronic items today, the TFT LCD monitor/television. This market also represents another large potential in the mid to long term. “By 2005 – 2006 LEDs will begin to make significant inroads into markets for indoor/outdoor lighting, automotive interior/exterior lighting, shipboard lighting gaming machines and toys.” (Dr. Robert Steele, Strategies Unlimited).
Substrate Materials
When it comes to substrate materials, compound semiconductors such as GaN dominate, particularly for blue, green and white LEDs. Orange and red toned devices are made in AlInGaP, with U.S., Japanese and German manufacturers leading the way. Furthermore, Taiwan is currently leading the world capacity for LED manufacturing and continues to further expand its manufacturing capacity, integrating in-house technologies such as MBE and MOCVD reactors capabilities. Taiwan has also transformed itself from only being a low cost high tech manufacturer to fostering a heavily vested industry in R&D efforts to improve product performance and create new SSL products.
The fabrication of SS-LEDs (ultra-bright and high-brightness) requires an understanding of optical properties of materials used how to manipulate and obtain thin films with the right mechanical and electrical properties and knowledge of the requirements for packaging, in order to achieve high efficiencies. It’s still quite an art and it requires a complex process. Wafer sizes remain relatively small, especially in the substrate materials such as GaN and AlInGaP, which currently do not exceed 3 inches for large production runs.
Evaporation and Sputtering Target Materials
Evaporation and sputtering target materials have evolved to the forefront of making these latest LED devices become effective while keeping the cost down. Materion Microelectronics & Services recognizes that manufacturing brighter LEDs at acceptable costs requires high performance fabrication processes and thin film material integrity and consistency. Furthermore, a comprehensive set of precious metal recovery services such as shield kit cleaning and wafer reclamation complement our operation and elevate product and service capabilities to a level of operating costs and yields.
Materion Microelectronics & Services has been the leader in evaporation materials for compound semiconductor devices. Our EVAPro™ process technology delivers proven short burn-in time due to its low gaseous impurities and overall purity optimization (controlled low level impurities) to deliver the best thin film characteristics with almost minimized particulates at the wafer level. Our global manufacturing facilities in the U.S., Taiwan, Philippines and Singapore offer a local service at a global scale to meet and exceed your thin film materials and material recovery requirements.
The LED industry has its collective eye on the $15B general illumination market. Eventually, solid state lighting will replace incandescent bulbs in most applications. So far, an effective white light at the right price is still elusive. An LED can now exceed the luminous efficiencies of incandescent light bulbs greater than 35 lumens per watt, according to Intertech, but the total light output and cost per lumen must improve to become competitive with existing low cost lighting technologies. That being said, it is only a matter of time where the cost per lumen on a standardized white LED will reach well below fluorescent.