| 摘要 |
PURPOSE:To obtain two GaAlAs epitaxial wafers concurrently by a method wherein an epitaxial layer of GaAlAs compound semiconductor is formed on both the sides of a GaAs substrate wafer through an epitaxial growth method, and then only the GaAs substrate wafer is selectively etched. CONSTITUTION:An epitaxial layer is made to grow on both the front and the rear of a substrate wafer 2. The front and the rear of the substrate wafer 2 are equivalent to each other in crystalline structure, so that the epitaxial layers 7 and 7 formed on both the sides of the substrate wafer 2 are equal to each other in composition and thickness. Then, etching liquid composed of ammonia and hydrogen peroxide is prepared for the selective etching of GaAs, the substrate wafer 2 where epitaxial layers have been grown is dipped into the etching liquid concerned and made to stand for one or two days, whereby the GaAs substrate wafer 2 located at the center is dissolved into the etching liquid. By this setup, the epitaxial layers 7 and 7 formed on both the sides of the substrate wafer 2 are separated off to serve as GaAlAs epitaxial wafers. |
