Open AccessPerformance of InGaN-Based Thin-Film LEDs With Flip-Chip Configuration and Concavely Patterned Surface Fabricated on Electroplating Metallic Substrate
Author(s) -
Xiao-Long Hu,
Zhao-Yi Qi,
Hong Wang,
Xi-Chun Zhang
Publication year - 2016
Publication title -
ieee photonics journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 73
eISSN - 1943-0655
pISSN - 1943-0647
DOI - 10.1109/jphot.2016.2516911
Subject(s) - engineered materials, dielectrics and plasmas , photonics and electrooptics
In this paper, a p-pad-up InGaN-based flip-chip (FC) thin-film light-emitting diode (TFLED) on electroplating metallic substrate was fabricated by a combination of electrodes isolation, FC configuration, copper electroplating, and laser lift-off techniques. This allowed formation of n-contacts on Ga-polar n-GaN and superior design of n-electrode pattern, resulting in an improved electrical performance when compared with the vertical-structure (VS) TFLED, in which the n-contacts need to be formed on N-polar n-GaN. In addition, the light output power was enhanced through this architecture due to the uniform current distribution and the absence of pads and wires on top of the FC-TFLEDs. It is found that the wall-plug efficiency of the FC-TFLEDs is 23.6% higher than that of the VS-TFLEDs. Moreover, the FC-TFLEDs with a concavely patterned surface were fabricated from the LED wafer with patterned sapphire substrate. Further improvement in output power was achieved when compared with that of the FC-TFLED fabricated from the LED wafer with flat sapphire substrate.