Excellent potential of photo-electrochemical etching for fabricating high-aspect-ratio deep trenches in gallium nitride. (10th August 2018)

• Record Type: Journal Article
• Authors: Horikiri, Fumimasa; Ohta, Hiroshi; Asai, Naomi; Narita, Yoshinobu; Yoshida, Takehiro; Mishima, Tomoyoshi
• Is Part Of: Applied physics express. Volume 11:Number 9(2018)
• Publication Date: 2018-08-10
• Subjects: Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.7567/APEX.11.091001
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: Photo-electrochemical (PEC) etching was used to fabricate deep trench structures in a GaN-on-GaN epilayer grown on n-GaN substrates. A 50-nm-thick layer of Ti used for an etching mask was not removed even after etching to a depth of >30 µm. The width of the side etching was less than 1 µm with high accuracy. The aspect ratio (depth/width) of a 3.3-µm-wide trench with a PEC etching depth of 24.3 µm was 7.3. These results demonstrate the excellent potential of PEC etching for fabricating deep trenches in vertical GaN devices.