Suppressing the Initial Growth of Sidewall GaN by Modifying Micron-Sized Patterned Sapphire Substrate with H3PO4-Based Etchant

Abstract

Micron-sized patterned sapphire substrates (PSS) are used to improve the performance of GaN-based light-emitting diodes (LEDs). However, the growth of GaN is initiated not only from the bottom c-plane but also from the sidewall of the micron-sized patterns. Therefore, the coalescence of these GaN crystals creates irregular voids. In this study, two kinds of nucleation layers (NL)—ex-situ AlN NL and in-situ GaN NL—were used, and the growth of sidewall GaN was successfully suppressed in both systems by modifying the micron-sized PSS surface.

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes

“…The wide bandgap GaN and related materials have been extensively studied and implemented for optoelectronic devices that emit light in the spectrum between ultraviolet and visible light [1,2,3,4,5,6,7]. GaN-based light-emitting diodes (LEDs) have been extensively adopted in a number of applications such as high-resolution micro-displays, automotive lighting, optogenetics, visible light communication (VLC), and solid-state lighting.…”

Editorial for the Special Issue on Wide Bandgap Semiconductor Based Micro/Nano Devices

“…An improved GaN HEMTs and their microwave performance by employing the asymmetric power-combining was reported by Kim et al [10]. Along with another GaN LED built on a modified micron-size patterned sapphire substrate by Hsu et al [11]. These GaN LED works are also guided broad readers in the field of optoelectronics and biomedical areas toward future high-performance optogenetics and photonics applications.…”

Suppressing the Initial Growth of Sidewall GaN by Modifying AlN-Coated Patterned Sapphire with KOH-Based Etchant

“…In our previous study, sulfuric-phosphoric acid was used to (1) modify PSS surface. 18 After etching, 3T {1 105} facets were found on the pattern sidewall. However, at the same time, 6B {3 417} facets were observed on the bottom c-plane.…”