公开(公告)号：JP2000068608A

公开(公告)日：2000-03-03

申请号：JP23684898

申请日：1998-08-24

Applicant: AGENCY IND SCIENCE TECHN

Inventor： SHIMIZU MITSUTOSHI ,  OKUMURA HAJIME ,  SHIRAKASHI JUNICHI ,  WATANABE MASANOBU

IPC: H01L21/308 ,  H01L33/32 ,  H01S5/00 ,  H01S5/323 ,  H01L33/00

Abstract: PROBLEM TO BE SOLVED: To enable wet etching with little damage by etching chemically stable gallium nitride using reactive pyrophosphoric acid. SOLUTION: A gallium nitride growing substrate, a holding device or the like are pre-heated to the same temperature as an etching temperature. Then the gallium nitride growing substrate is soaked in pyrophosphoric acid to be etched. Optimum time to soak should be calculated by pre-conditioning. A temperature of pyrophosphoric acid should be also calculated similarly. Pyrophosphoric acid can be obtained by dehydrating orthophosphoric acid which is usually used. Or it can be obtained by adding water of a suitable ratio to phosphorus oxide. In addition, sufficient etching speed can be obtained by raising the temperature of the pyrophosphoric acid to a high temperature ranging from 210 to 220 deg.C or higher. Then after the time required for etching, materials are taken out, and the pyrophosphoric acid remaining on surfaces is removed using pure water.