Premium
Optimization of electrode structure for flip‐chip HVLED via two‐level metallization
Author(s) -
Cai Yuefei,
Zou Xinbo,
Chong Wing Cheung,
Lau Kei May
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532803
Subject(s) - electrode , materials science , optoelectronics , flip chip , passivation , reflector (photography) , substrate (aquarium) , current (fluid) , voltage , chip , photolithography , electrical engineering , optics , composite material , layer (electronics) , chemistry , engineering , light source , adhesive , physics , oceanography , geology
In this article, we demonstrated an optimized electrode structure for high voltage LED (HVLED) using a two‐level metallization technique. The first‐level metallization is to form interdigitated p and n electrodes with narrow metal fingers. After passivation, a second‐level reflective metallization was deposited to form a continuous reflector. Comparing the performance of HVLEDs with bar shape electrode, square shape electrode, and n finger interposed electrode, the HVLEDs with interdigitated p and n finger electrodes show better current uniformity, higher light output power (LOP) and larger wall plug efficiency (WPE). The LOP of such single HVLED chip with 8 sub LED cells on pattern sapphire substrate sample reaches 500 mW at 100 mA current injection. Using flip‐chip bonding technique to connect four such chips serially, LOP can reach 2 W at 100 mA drive current. The high brightness HVLED with optimized electrodes enables flexible driver designs for solid state lighting and other applications.