| 摘要 |
PURPOSE:To obtain a recess type fine multi-layer gate electrode with excellent highfrequency characteristics by a method wherein metal films of Mo, Pt and Au are formed on a semiconductor substrate and a mask is formed on them and the metal films are removed by etching except those under the mask. CONSTITUTION:A metal film 20 of Mo is formed on a GaAs semiconductor substrate 1 by beam deposition in high vacuum at 200-300 deg.C and then a metal film 30 of Pt is formed. Then the substrate is heated at 100 deg.C and a metal film 40 of Au is formed. Then the substrate is taken out in the atmosphere and a Ti film 50 is formed on the film 40 and a mask 60 of photoresist is formed to the required gate region. After that the metal film 40 of Au, the metal film 30 of Pt and the metal film 20 of Mo are removed by etching except those under the mask 60 and the Ti film 50. Moreover, a source electrode 80 and a drain electrode 90 are formed by lifting-off using conventional resist and a GaAs FET which has a recess type fine multi-layer gate electrode can be obtained. |
