Foxconn Patents Nanoparticle LED Doping
Electronics manufacturer Foxconn is challenging established LED chip companies and their methods with two US patent applications that exploit nanoparticle dopants to improve performance.
Hon Hai Precision Industry Co, which trades under the name Foxconn and makes products for Nokia, Apple, Dell and many others, 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 multi-quantum well layers in application numbers 20090134406 and 20090134380.
In an otherwise typical LED epitaxial structure, the confinement layers either side of the active layers exploit nanoparticles 20-200 nm in diameter as dopants.
The nanoparticles can be either SiN, SiO, GaO, AlN or BN, and help 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 writes.
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," says the patent.
In April 2001, Hon Hai Precision set up Foxsemicon Integrated Technology Inc. (FITI) as a TFT-LCD, LED lighting and LED display production subsidiary.
Since 2006 a handful of patents have been filed in the US attributed to Hon Hai Precision, FITI, and Foxconn relating to production of LED chips.