| 摘要 |
PURPOSE:To prevent the formation of an inversion layer, by providing the fourth electrode on the surface of a channel region. CONSTITUTION:On an N type GaAs active layer 2 formed on a GaAs substrate 1, a source electrode 4 of an AuGe alloy layer and an Au layer and a drain electrode 5 are formed. Next, a photo resist film 12 having an aperture 11 is formed, and, with it as a mask, a recess 13 is formed. Then, the photo resist film 12 is removed, a photo resist film 14 is newly formed, Al is adhered, a gate electrode 3 is formed, and accordingly the photo resist film 14 and the Al layer 3' are formed. Over the entire surface on the substrate, an Si dioxide film 15 is adhered, then an Al layer is formed thereon, and a photo etching is performed resulting in the formation of the fourth electrodes 16 and 16'. Thereafter, contact windows 17 and 18 are opened on the source electrode and the drain electrodes 4 and 5. When the source electrode 5 is earthed and a positive voltage is impressed on the drain electrode 4 and the electrodes 16 and 16', electrons are drawn near to the surface of the channel region 9, accordingly the inversion layer disappears. |
