The application of nano imprint technology can improve the LED luminescence efficiency 20-30%
Nanoscale imprint refers to the technology of transferring a fine pattern of die to the top of a substrate, such as a seal, like a seal. Recently, more and more cases of this technology have been applied.
Production of LED molds by R2R
The technology of fine pattern formation using nano imprint technology helps to improve the luminescence efficiency of LED and organic EL. Toshiba machinery has developed a technology that includes a special embossing device to increase the luminous efficiency of LED by 20 to 30%. We use the "PSS" (Patterned Sapphire Substrate) patterned sapphire substrate on the surface of sapphire substrate to improve the reflectivity and so on, thereby improving the luminous output.
Gotou Hiroshi, Deputy business secretary of Toshiba mechanical nano processing system department, said the problem is how to reduce the number of mold defects, and how to make the cost more advantageous than using existing stepper to form patterns. "If the substrate is defective, LED will not glow. In order to reduce the cost of repeated use of the mold, the defects will be more and more.
The company's response to these two problems is to make a one-time product with a large copy of the resin mold using R2R. The 4 inch wafer cost less than $5 goal has taken shape". The resin mold also has one advantage, which is a sapphire substrate that is not necessarily flat.
Realization of high quality GaN crystal
Recently, the possibility of using nano imprint technology to further improve the efficiency of LED has also emerged. In the laboratory of Mizuno Jun, an associate professor of Waseda University, Jinze Industrial University, Toshiba machinery and Waseda University, the dislocation of GaN crystal was developed by using nanoimprint technology. The dislocation density of GaN crystal is more than 1 * 109/c square meters, is considered to be the reason for a decrease in luminous efficiency to LED high current flows). Down to about 1% of the original method.
The specific methods are as follows: first, form SiO2 thin films on the original GaN crystals, and form dozens of nm wide small openings by using nanoimprint technology, then grow GaN crystals again. In this way, the dislocation of the GaN crystal below the SiO2 film will not reach the above GaN crystal, thereby reducing the dislocation of the above GaN crystal. "We tried the LED to make sure that the technology could increase output power and prolong life," said the professor of water field at the Waseda University. It should also be used for power semiconductors.