Open AccessThermal-assisted contactless photoelectrochemical etching for GaN
Author(s) -
Fumimasa Horikiri,
Noboru Fukuhara,
Hiroshi Ohta,
Naomi Asai,
Yuji Narita,
Takehiro Yoshida,
Tomoyoshi Mishima,
Masachika Toguchi,
Kenji Miwa,
Hiroki Ogami,
Taketomo Sato
Publication year - 2020
Publication title -
applied physics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.911
H-Index - 94
eISSN - 1882-0786
pISSN - 1882-0778
DOI - 10.35848/1882-0786/ab7e09
Subject(s) - oxidizing agent , etching (microfabrication) , electrolyte , chemistry , alkali metal , titration , inorganic chemistry , ion , analytical chemistry (journal) , chromatography , electrode , layer (electronics) , organic chemistry
Advanced contactless photoelectrochemical etching for GaN was conducted under the condition that the sulfate radicals (SO 4 ·− ) as the oxidizing agent were mainly produced from the S 2 O 8 2− ions by heat. The generation rate of SO 4 ·− was determined from the titration curve of the pH in the mixed solutions between KOH (aq.) and K 2 S 2 O 8 (aq.); it clearly increased with an increase in the S 2 O 8 2− ion concentration. The highest etching rate of >25 nm min −1 was obtained in the “alkali-free” electrolyte of 0.25 mol dm −3 (NH 4 ) 2 S 2 O 8 (aq.) at 80 °C, which was approximately 10 times higher than that reported by previous studies.