Title :
Sacrificial Structure for Effective Sapphire Substrate Liftoff Based on Photoelectrochemical Etching
Author :
Chieh Hsieh ; Chia-Ying Su ; Chi-Ming Weng ; Ting-Ta Chi ; Yean-Woei Kiang ; Chih-Chung Yang
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
The photoelectrochemical (PEC) liftoff results and the performances of fabricated vertical light-emitting diodes (LEDs) among four samples of different PEC etching sacrificial structures are compared. With a dopant-graded n-GaN sacrificial layer, the PEC liftoff time is decreased. With an n-AlGaN etching-stop layer, the roughness of PEC-etching surface is significantly reduced for simplifying the following device process. Illuminated by an ultraviolet LED array at 365 nm in emission wavelength, the PEC liftoff of a 2-in wafer with device isolation can be completed in 25 min. The performances of the fabricated vertical LEDs with different sacrificial structures are similar.
Keywords :
III-V semiconductors; aluminium compounds; etching; gallium compounds; isolation technology; light emitting diodes; optical arrays; optical fabrication; photoelectrochemistry; surface roughness; wide band gap semiconductors; Al2O3; AlGaN-GaN; PEC etching sacrificial structures; PEC-etching surface roughness; device isolation; dopant-graded n-GaN sacrificial layer; emission wavelength; etching-stop layer; photoelectrochemical etching; photoelectrochemical liftoff; sapphire substrate liftoff; ultraviolet LED array; vertical LED; vertical light-emitting diodes; wavelength 365 nm; Epitaxial growth; Etching; Gallium nitride; Light emitting diodes; Rough surfaces; Substrates; Photoelectrochemical liftoff; photoelectrochemical liftoff; sacrificial structure; vertical light-emitting diode;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2015.2392108
