Abstract: A field-effect transistor comprises an ancillary electrode in addition to the source, gate and drain electrodes. In this device, a semiconducting body bears source, gate and drain metallizations which define a main transistor. The metallization of the drain is separated into two parts which are separated by a channel on which is placed a second gate metallization defining a secondary transistor. The two parts of the drain are coupled by this secondary transistor, the channel of which is separated from the main channel. The secondary transistor can be used to control the gain of the main transistor or to modulate its amplitude signal or to mix two frequencies addressed on the two gates.

Abstract: A microwave transistor made with group III-V materials, such as GaAs and AlGaAs, is disclosed. This transistor essentially comprises a double heterojunction formed by a first layer of material with a big forbidden gap, n doped for example, a second non-doped layer with a narrow forbidden gap and a third p doped layer with a wide forbidden gap. Under the effect of the electrical field, there may be formed, simultaneously or not simultaneously, in the second layer, a two-dimensional electron gas at the interface with the first layer and a two-dimensional hole gas at the interface with the third layer. By bringing the thickness of the layers into play, the characteristics of the n and p channels can be made symmetrical.

Abstract: A junction-type field-effect structure has an active layer covered at least in part by a dielectric layer. A metal base is applied to the dielectric layer.