| 摘要 |
PROBLEM TO BE SOLVED: To surely remove an oxide film on the surface of an AlGaAs layer generated by a selective etching, in a recess-gate type FET. SOLUTION: In a process for manufacturing a recess-gate type FET, a recess etching process (S105) subjects it to an aqueous solution containing aqueous ammonia for selective etching with GaAs in wet-etching. An aluminum oxide film generated on the surface of an AlGaAs layer at the lower part GaAs in the recess etching process is removed (S106) in an aqueous phosphate. The temperature of the aqueous phosphate is kept at 30 deg. or below and only an oxide film is removed.
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