| 摘要 |
PURPOSE:To uniformly form the gate length of 0.5 mum or less in an excellent reproducible manner by a method wherein a groove having forward mesa type cross-section is formed on the top layer of semiinsulating AlGaAs layer in such a manner that the groove reaches the N-type GaAs layer located under the AlGaAs layer, and a gate metal is formed in the groove. CONSTITUTION:A high resistance AlGaAs layer 16 is provided on the N-type GaAs layer 4 located on an N-type AlGaAs layer 3, and a groove having forward mesa type cross-section and reaching the N-type GaAs layer 4 is formed on said high resistance AlGaAs layer 16 by performing selective etching on the high resistance AlGaAs layer 16, and a gate metal electrode 10 is formed in the groove. By utilyzing the inclination of the forward mesa type groove cross-section, the width of the groove bottom contacting to the N-type GaAs layer 4 can be narrowed down to 0.5 mum or less through the AlGaAs layer 16 even when the width of a mask is 0.5 mum on the surface. Moreover, the reproducibility of the width of the bottom of said groove is excellent. Also, as the N-type GaAs layer 4 is used as the stopper of an etching groove, the etching groove having excellent reproducibility and the uniformity in the wafer can be formed easily. |
