| 摘要 |
<p>A wafer comprising a GaAs substrate and an AlGaAs layer deposited thereon is rotated in a spin etching process. To the GaAs substrate of the rotating wafer, there is supplied an ammoniacal etching solution for selectively etching the GaAs substrate to form a groove therein. The ammoniacal etching solution comprises a mixture of hydrogen peroxide and aqueous ammonia, the volume ratio of hydrogen peroxide and aqueous ammonia being in the range from about 20 to 60. While the GaAs substrate is being selectively etched by the ammoniacal solution, the rotational speed of the wafer is progressively increased stepwise or continuously. The etching solution whose volume ratio of hydrogen peroxide and aqueous ammonia is in the range from about 20 to 60 is suitable for the formation of a deep groove in the GaAs substrate. The rotational speed of the GaAs substrate is progressively increased stepwise or continuously to progressively increase centrifugal forces applied to the GaAs substrate for thereby expelling a substance, which is generated in reaction with the etching solution, off the GaAs substrate. Since such a substance is prevented from being deposited on the GaAs substrate, the etching process progresses uniformly without an etching failure.</p> |
