| 摘要 |
PURPOSE:To enable operation at high speed by introducing a doner impurity into a semiconductor on the gate electrode side having narrow forbidden band width in a gap region between a channel and source-drain electrodes. CONSTITUTION:An AlGaAs layer 22 is grown on a semi-insulating GaAs substrate 21, and a GaAs layer 23 is grown. Impurity concentration in the layer 23 is brought to 1X10<15>cm<-3> or less. A gate electrode 28 is attached onto the layer 23, and Si ions 31 are implanted while using the electrode 28 as a mask to form an impurity region 24. A source 25 and a drain electrode region are shaped connected to the layer 24, and electrodes 29, 30 are shaped. Impurity concentration is brought to 10<16>cm<-3> or more in regions except a section in the vicinity of a region, in which carriers 32 are induced, in the layers 23, 22 just under the electrode 28. Accordingly, operation at ultrahigh speed is enabled because there are an extremely small quantity of impurities functioning as the center of scattering in a region, in which carriers 32 travels, or a region adjacent to the region.
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