| 摘要 |
PURPOSE:To reproduce the same gate form as a gate pattern by converting the gate pattern into a shape that the gate pattern is inverted as a gate opening to a plasma nitride film, executing heat treatment through which crystallinity is recovered while the verticality of a wall surface and gate length are left as they are kept, and burying the gate opening with a gate metal again. CONSTITUTION:An operating layer 5 consisting of an N type impurity is formed on a semi-insulating GaAs substrate 4, aluminum Al is evaporated on the whole surface on the N type operating layer 5, a gate pattern 21 is formed through side etching while using a photoresist film as a mask, the whole surface is coated with the plasma nitride film 22 as a coating film, and the periphery of the N type operating layer 5 is coated with a photoresist film 23. The photoresist film 23 is removed, and a photoresist film 24 is applied and dried. The whole surface is etched through parallel plate dry etching using CF4 gas to expose the Al gate pattern 21, the residual photoresist film 24 is removed by an exfoliating liquid, the Al gate pattern 21 is removed through etching to form a gate opening 25, an oxide film 26 is grown to coat the gate opening 25 and used as an annealing protective film, and the crystallinity of the operating layer 5 and an N<+> conductive layer is recovered through heat treatment. |
