| 摘要 |
PURPOSE:To remove an anodic oxidized film completely from the surface of InP and to prevent under-etching by carrying out etching using 5-20% aq. phosphoric acid soln. as an etching liquid for the anodic oxidized film on InP. CONSTITUTION:An anodic oxidized film of InP which is a material for a light emitting and photodetecting element and FET is removed by etching with 5- 20% aq. phosphoric acid soln. It has been found that there is no fear of causing under-etching when phosphoric acid or HF+NH4F is used for the etching treatment among several etching liquieds including 10% H3PO4, 10% H2SO4, 10% HCl, HF+NH4F (45:500). However, residues are liable to remain on the surface of InP when HF+NH4F is used. Therefore, etching causing no under-etching, without remaining residual product, is only possible by using aq. phosphoric acid.
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