Wet Etching of Amorphous TiO sub(2) Thin Films Using H sub(3)PO sub(4-) H sub(2)O sub(2) Aqueous Solution

• Published in: Japanese Journal of Applied Physics Vol. 52; no. 9R; p. 098002
• Main Authors: Okazaki, Sohei, Ohhashi, Takuya, Nakao, Shoichiro, Hirose, Yasushi, Hitosugi, Taro, Hasegawa, Tetsuya
• Format: Journal Article
• Language: English
• Published: 01.09.2013
• Subjects: Aqueous solutions; Etching; Niobium; Thin films; Titanium dioxide
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.52.098002

We report on the wet etching of amorphous undoped and Nb-doped TiO sub(2) thin films using H sub(3)PO sub(4-)H sub(2)O sub(2) etching solution. The etching rate (R) showed a maximum at a H sub(3)PO sub(4) concentration of approximately 50 wt % at 80 [degrees]C, suggesting that H sub(2)PO sub(4-) and/or H sub(3)O sub(+) is responsible for the etching reaction. The addition of H sub(2)O sub(2) to H sub(3)PO sub(4) solution significantly enhanced R, and an optimized solution exhibited an R of 13 nm/min at 80 [degrees]C, which is one order of magnitude higher than that using H sub(2)SO sub(4). These results demonstrate that H sub(3)PO sub(4-)H sub(2)O sub(2) aqueous solution is an effective etchant for TiO sub(2)-based amorphous thin films.