Foxconn Patents Nanoparticle Doping
Hon Hai Precision Industry Co, which trades under the name Foxconn and makes products for Nokia, Apple and Dell, filed two applications on May 28. Judged by some to be the largest electronics producer in the world, Foxconn has claimed LEDs that use hydrogenated SiC as their substrates.
The Taiwan-headquartered company has patented LEDs that can use either InGaN or AlGaAs as their active, single or multiquantum-well layers in application numbers 20090134406 and 20090134380. In an other wise typical LED epitaxial structure, the confinement layers either side of the active layers exploit nanoparticles 20–200 nm in diameter as dopants.
Nanoparticles can be made from SiN, SiO, GaO, AlN or BN, and help to improve the crystal quality of the die, writes listed inventor Ga-Lane Chen. Chen is chief technology officer and vice-president of global R&D at Hon Hai Precision Industry. “The nanoparticles can change the lattice constant [of] the n-type and p-type confinement layers and decrease the lattice strain thereof," Chen said.
By reducing the strain, fewer dislocations form when the active layer is deposited on the n-type confinement layer and when the p-type layer is deposited on the active layer. “The decrease of lattice strain weakens the stress generated between the active layer and the confinement layers, and the quantum efficiency is improved," stated the patent.