GaAs (111) wafer cleaning method

The invention discloses a GaAs (111) wafer cleaning method. The GaAs (111) wafer cleaning method comprises steps that, a GaAs (111) substrate is treated by an organic solvent to remove oil stain and organic matters on the surface; the GaAs (111) substrate is immersed in hydrogen peroxide, is then taken out, is cleaned by deionized water, is immersed in hydrochloric acid, is taken out and is cleaned by deionized water; the acquired GaAs (111) substrate is immersed in hydrogen peroxide, is cleaned by deionized water, is immersed in hydrochloric acid and is cleaned by deionized water for at least one time. According to the method, the surface of the GaAs (111) substrate is treated by the hydrogen peroxide to acquire a structured nature oxide layer and is then corroded by the hydrochloric acid, as the GaAs (111) surface is the structured nature oxide layer, GaAs defects with bad quality in the surface can be effectively removed, so oxide quantity and roughness of the GaAs surface can be greatly reduced. The cleaning method is employed in combination with an ammonium sulphide solution for passivation, so the clean GaAs surface can be prevented from being oxided by oxygen in the air for long time.