Open AccessUV light-emitting diodes grown on GaN templates with selective-area Si implantation
Author(s) -
Ming Lun Lee,
Po Hsun Liao,
Hsin Yan Cheng,
Wei Yu Yen,
Jinn-Kong Sheu
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.386512
Subject(s) - materials science , optoelectronics , light emitting diode , epitaxy , template , layer (electronics) , ion implantation , diode , amorphous solid , silicon , nanotechnology , ion , crystallography , chemistry , organic chemistry
This study demonstrates that selective-area Si implantation performed on the GaN templates instead of conventional dielectric layers, such as SiO 2 or SiN x , serves as the mask layer for the epitaxial lateral overgrowth (ELOG) process. Although the substantial mask layer is absent on the templates, selective growth initially occurs on the implantation-free area and then evolves a lateral overgrowth on the Si-implanted area during the regrowth process. This selective growth is attributed to that the crystal structure of the Si-implanted area subjected to the high doses of ion bombardment produces an amorphous surface layer, thereby leading to a lattice mismatch to the regrown GaN layer. Microstructural analyses reveal that the density of the threading dislocations above the Si-implanted regions is markedly lower than the GaN layer in the implantation-free regions. Consequentially, UV LEDs fabricated on the Si-implanted GaN templates exhibit relatively higher light output and lower leakage current compared with those of LEDs grown on ELOG-free GaN templates.