| 摘要 |
PURPOSE:To obtain GaAs FET's with improved withstant voltage and improved high frequency performance by a method wherein a gate electrode made of high melting point metal is formed by a normal lift-off method by means of a double- layer photo resin film having different speeds of development. CONSTITUTION:An n type region 4 is formed on a semi-insulation GaAs substrate 1. A photo resist 6 is applied, and the sped of development is reduced by soakage in monochlorobenzene. A photo resist 10 is applied and a gate electrode pattern is formed by photo engraving. The lateral spreading of the developed pattern differs between the photo resists 6 and 10. A high melting point metal 11 is formed, and a T-type gate metal 12 made of a high melting point metal film 11 is formed by the lift-off method. An n type semiconductor layer 4' and an n<+> semiconductor layer 7' are formed, and a source electrode 8 and a drain electrode 9 are formed. Since the T-type gate electrode 12 and the n<+> semiconductor 7' do not come into direct contact with each other, the gate-source withstand voltage and the drain-source withstand voltage can be markedly increased. |
