Technical method for flatting surface of triple-junction gallium arsenide epitaxial layer

The invention relates to a technical method for flatting the surface of a triple-junction gallium arsenide epitaxial layer. The method comprises the steps that after two polishing solutions are prepared, a wafer is placed in a wax-free pad glued to a press block; a damping cloth on a polishing disc is tightly attached to the surface of the triple-junction gallium arsenide epitaxial layer, a self-inspection procedure is executed, and the self-rotation conditions of the press block and the wafer are checked; after execution of the self-inspection procedure is ended, the first kind of polishing solution is applied, and a first section of polishing process is executed; after the first section of process is ended, application of the first kind of polishing solution is stopped, the second kind of polishing solution is applied, and the second section of process is executed; after the second section of process is ended, application of the polishing solutions is stopped, and the wafer is takenout from the interior of