| 摘要 |
PURPOSE:To attach an electrode to an intermediate film of multilayer film by forming a connecting hole only to the electrode region, depositing an insulator thereto and forming an electrode through removal of insulator from the bottom surface of connecting hole. CONSTITUTION:A p type layer 11 is provided to a half-insulating GaAs substrate 10 and a gate electrode 15 and an SiO2 14 are also provided by stacking a GaAs 12 and an n type AlxGa1-xAs 13. An ohmic electrode can be attached to a p type layer 11 by providing a resist mask 16, etching it with an etchant of HF:NH4F=1:15 and thereafter etching AlxGa1-xAs, GaAs with the NH4OH system solution. Thereafter, a mask 16 is removed and the surface is covered with CVD SiO2 15. The anisotropic etching is carried out using a mixed gas of NF3 and N2 in the parallel plate type apparatus, leaving SiO2 17'' at the side wall of hole. An ohmic electrode of Cr-Au 18 is attached to the exposed hole bottom of substrate. This method is particularly suitable for formation of electrode to a specific layer in the epitaxial layers. |
