| 摘要 |
PURPOSE:To make an operation speed higher without the restriction of the width of a gate electrode by a method wherein a step is provided in the junction boundary of a first compound semiconductor layer and a second compound semiconductor layer at the position between a source electrode and a drain electrode. CONSTITUTION:A depletion type HEMT comprises a substrate of a first compound semiconductor, and an n-type AlGaAs layer 11 of a second semiconductor, which is formed on the substrate where an epitaxial i-GaAs layer 10 may or may not be present. A source electrode 12 and a drain electrode 13 which are made of AuGe/Ni and a gate electrode 14 which is made of Al are provided on the n-type AlGaAs layer 11. Further, a step about 10mm high is provided in the junction boundary of the i-type GaAs layer 10 and the n-type AlGaAs layer 11 at the position between the source electrode 12 and the drain electrode 13. With this constitution, a 2DEG layer 20 having a step is formed in the junction boundary of the i-type layer 10 and the n-type AlGaAs layer 11 with the n-type AlGaAs layer 11 as an electron donor layer. |
