| 摘要 |
PURPOSE:To prevent deformation of the shape of a depletion layer due to the intrusion of gas, liquid and the like in the vicinity of a gate electrode and in the surface of GaAs and to prevent fluctuation in characteristics of a transistor, by constituting a passivation film, which is formed on gate, source and drain electrodes in at least three layers of a nitride film, on an oxide film and a nitride film. CONSTITUTION:On a GaAs semi-insulating substrate 1, a buffer layer 2 and a mesa shaped operating layer 3 are provided. A gate electrode 4, which constitutes a Schottky barriers in a recess formed in the operating layer 3, is formed by a double-layer structures of titanium 4a and aluminum 4b. On both sides of the recess, a source electrode 5 and a drain electrode 6 made of AuGe.Ni, which are resistively contacted, are formed. The gate electrode 4 is converted with a nitride film 7. The electrode 4, 5 and 6 are converted with an oxide film 8 and a nitride film 9. Windows are provided at places corresponding to the source and drain electrodes 5 and 6 in the nitride film 7. Metal wiring layers 10 and 11 in a laminated layer structure of Ti-Pt-Au are formed in the required pattern. A nitride film 12 is formed on the entire surface except bonding pads 10a and 11a so as to cover the electrodes 4, 5 and 6.
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