Formation of gate electrode

Abstract

Abstract PURPOSE:To improve electrical properties and reliability by a method wherein an opening is formed of which section is bowl-shaped and a gate electrode forming metal deposited on a surface which contains the opening is selectively etched for the formation of a Y-shaped gate electrode. CONSTITUTION:The rest of an opening of an aluminum film 3 is removed by anisotropic etching using a CCl4+He gas through a silicon oxide film 4 used as a mask so as to expose the surface of a GaAs active layer 2 and form an opening 6 of which section is bowl-shaped. Next, a silicon oxide film 8 is formed on a surface which contains the opening 6 after the silicon oxide film 4 is removed. After that, the silicon oxide film 8 deposited on the part other than a vertical side wall of the opening 6 is removed, and WSi, Ti, Pt, and Au are deposited on the surface which includes the opening successively through a sputtering method and then selectively etched in succession for the formation of a gate electrode 9. Further, the aluminum layer 3 and the silicon oxide film 8 are removed successively for the formation of the Y-shaped gate electrode 9. By these processes, the gate electrode is reduced in a parasitic resistance and improved in high frequency properties.

Inventors

• 👤 Hitoshi Ito

Bibliographic Details