| 摘要 |
PURPOSE:To make perfect the removal of resist in the lift-off process by a method wherein, after metal has been evaporated, a degenerative layer of the exposed resist is exposed to oxygen gas in the plasma and removed by an usher. CONSTITUTION:An SiO2 film is formed on a GaAs substrate 1 formed with a conductive layer 1' through the ion injection method and then positive resist 3 is applied thereto to make a window through the photoresist etching method. Subsequently, the substrate is exposed to CF4 gas in the plasma to remove the SiO2 film. At this time, an alternated film 4 is formed on the surface of the resist. Then AuGe alloy 5 which is to become an ohmic electrode is evaporated against the GaAs conductive layer 1'. The substrate is then exposed to the plasma pressurized by oxygen gas for five minutes to remove the exposed alternated layer 4. When the substrate was soaked in aceton, the resist 3 and the AuGe alloy 5 were readily removed, making it possible to form the ohmic electrode after heat treatment over the whole surface of the wafer with high yielding ratio. |
