| 摘要 |
PURPOSE:To enable a mutual conductance larger than conventional to be obtained by the variation of the effective gate length with gate voltage, by a method wherein the direction of a groove forming a stripe end of a gate electrode is made vertical to the line combining a source electrode with a drain electrode. CONSTITUTION:Hetero junctions made of the first semiconductor layer 12 and the second semiconductor layers 13, 14 of the same conductivity type having large differences in electron affinity are formed. In the surface of the second semiconductor layers, e.g. AlGaAs layers 13, 14 of small electron affinity formed on the first semiconductor layer, e.g. GaAs layer 12 of large electron affinity, a gate electrode 17 having many stripe ends 17a is formed. The thicknesses of the second semiconductor layers 13, 14 are made large at the ends 17a enough to gate-voltage-control the number of carriers 18 accumulated in the interface between the first semiconductor layer 12, and the direction of grooves forming the ends 17a is made almost vertical to the line combining the source electrode 15 with the drain electrode 16. This construction causes the effective gate length to vary with gate voltage, and the mutual conductance with changes of the gate length; therefore, the increase in mutual conductance Gm can be contrived. |
