| 摘要 |
PURPOSE:To increase mutual conductance and cut-off frequency by inserting a barrier layer, consisting of a semiconductor the magnitude of the energy discontinuity of a conduction band of which between a semiconductor layer as a conductive channel and the semiconductor is smaller than the sum of valley energy forces in the conduction band of the semiconductor layer as the conductive channel, under the semiconductor layer as the conductive channel. CONSTITUTION:A non-doped AlxGa1-xAs layer 12 to which an impurity is not added is grown onto a non-doped semi-insulating GaAs substrate 11, and the Al mol ratio of the layer is set between 0.4 and 0.8. A non-doped GaAs layer 13 as a channel layer, an n-type Al0.8Ga0.7 As layer 14 containing Si as an impurity and an n-type GaAs layer 15 containing Si as an impurity are grown onto the AlGaAs barrier layer 12. A wafer is grown, and elements are isolated through mesa etching with the exception of element regions. Sourcedrain electrodes 16, 17 are formed, a gate resist pattern is shaped, one parts of the n GaAs layer and the n Al0.8Ga0.7As layer under the pattern are removed to prepare a recessed shape, and a gate electrode 18 composed of Al/Ti is shaped into a recessed region. Accordingly, the title transistor displaying high mutual conductance and cut-off frequency is acquired. |
