| 摘要 |
PURPOSE:To suppress the formation of a protective film to undesired portion by forming a mask having a metal layer and a hole, selectively etching the metal layer, then forming the protective film, and then completely removing the metal layer. CONSTITUTION:An ohmic electrode 11 made of Au-Sn alloy is formed on one main surface N type GaAs substrate 12, and a mask 15 which has a metal layer 13 made of In and a hole 14 and made of SiO2 is formed. The layer 13 is selectively etched so that the mask 15 becomes an overhang with respect to the substrate 1 from the surface of the hole 14. The substrate 12 is cleaved along the hole 14, and Al2O3 is deposited by sputtering on the cleaved surface to form a protective film 16. At this time, the surface of the electrode 11 is coated with the layer 13, and the portion not coated is presented with the mask 15 as an overhang. Accordingly, the Al2O3 is not deposited. Finally, the layer 13 and the mask 15 are removed. Thus, the film 16 can be formed only on the surface of the substrate 12. |
