| 摘要 |
PURPOSE:To provide a GaAs substrate with an activation layer at a shallow level by a method wherein ions are implanted into a GaAs substrate through a thin GaAlAs film, a thin insulating film is formed, annealing is accomplished, and the GaAlAs film is removed together with the thin insulating film. CONSTITUTION:A Ga1-xAlxAs thin film 2 is provided on a GaAs substrate 1. Si ions are implanted through the thin film 2 into a layer 3', whereupon a CVD SiO2 layer 4 is deposited. Annealing is accomplished in H2 for the formation of an activation layer 3, when little is lost of the Ga contained in the GaAs substrate 1. After the heat treatment, the stress exerted by the SiO2 layer 4 upon the GaAs substrate 1 is mostly borne by the thin film 2, affecting the substrate crystals only a little. Next, necessary, the SiO2 layer 4 and the Ga1-xAlxAs thin film 2 are removed in that order by using a prescribed etchant. In this design, implanted ions are easy to be activated, a GaAs activation layer with a high carrier mobility may be provided at a level very near to the surface, all of which contribute to the production of a GaAs element for an IC capable of high-speed operation. |
