New substrate developments tackle one of LEDs un-desirable character traits “Droop”
LEDs inherently operate better at lower currents, in fact as the current increases the efficiency drops at a calculable rate. The cause of this “droop” is directly related to the composition of the substrate material. Using a composition similar (or identical) to the properties of the LED gallium (doped) nitrate crystal lattice, enhances thermal expansion properties, eliminate separation issues and increase energy efficiency.
Gallium nitrate-based substrates: possibly a major breakthrough While there is nothing new about using gallium nitrate as a substrate, growing large gallium nitrate crystals have been unobtainable, impractical or not cost-effective up to this point.
Silicon Valley startup “Soraa” (founded by three UCSB professors – Steve DenBaars, Jim Speck, and Shuji Nakamura) announce its first GaN-on-GaN LEDs.
Shuji Nakamura made a huge contribution to the development of the LED industry during his time at Nichia in the 1990s. More recently, he is known to have worked extensively on growing gallium nitride (GaN) material on GaN substrates. Rather than heading into the fierce LED package competition (like Cree and Bridgelux), Soraa incorporated their newest GaN-on-GaN LEDs into finished MR16 lamps.
Gallium-based crystal extrudes on Sapphire substrates are the current norm in LED manufacturing.
Sapphire crystal has been widely used, although fairly expensive, it allowed manufacturers to grow fairly large diameter crystals on which the LEDs can eventually be grown by epitaxy on top of sapphire substrates.
Silicon-carbide and silicon substrates reduce manufacturing material costs
As prices rise for Sapphire, silicon-based substrates are becoming more common with the larger manufacturers such as Osram-Sylvania and are viewed as a major cost-cutting breakthrough.Meanwhile American-based LED giant Cree, markets its silicon-carbide substrate-based LEDs around the world for hundreds of secondary manufacturers incorporate into their local LED products.
The Changing Shape of LED Chips
SMD (surface mount diodes) as well as most other types of LEDs currently use round, rectangular or square shaped chip technology. Soraa 's new MR 16 incorporates its interesting triangular shaped gallium nitrate on gallium nitrate LED light engine