| 摘要 |
PURPOSE:To obtain electric fields for increasing the drift velocity of carriers in a channel region with the utilization of piezoelectric polarization, by selecting the type of an insulation film to be provided near the gate electrode of a compound semiconductor FET. CONSTITUTION:Si ions are implanted into the (100) plane of a semi-insulating GaAs substrate 1 to form an N type channel layer 2. A gate electrode 3 is then formed such that the width of the gate is directed in the (01-1) direction. Ions are implanted with the use of the gate electrode 3 as a mask to form an N<+> type source and drain regions 4, and source and drain electrodes are provided thereon. An SiO2 film 6 and an Si3N4 film 7 are adhered on the source side and on the drain side, respectively. Accordingly, piezoelectric polarization is caused by the stress exerted on the semiconductor substrate by the insulation films such that the source side has the negative polarity and the drain side has the positive polarity. The drift velocity in the channel can be increased by these electric fields, and thus the characteristics of the FET can improved. |
