FIELD TRANSISTOR

The invention relates to semi-conductor devices and can be used for radiotechnical and UHF-devices, etc. The structure of the inventive field transistor is based on Ga and Al nitrides and consists of in series arranged substrate, an insulating layer made of ALxGa 1-xN, a channel layer and a barrier layer made of ALzGa 1-zN. Said channel layer is made of ALxGa 1-xN, wherein 0.12>x>0.03, 1>/=y>/=x+1 at the boundary between the channel and insulating layers, 1>/=z>/=x+1 at the boundary between the channel and barrier layers, the thickness of the channel layer ranges from 3 to 20 nm, x, y, z, being the Al molar fractions of a AlGaN compound. Said insulating layer can be embodied in the form of two sublayers in such a way that the lower sublayer, adjacent to the substrate is equal to 0.5-0.7 at the boundary therewith, is equal to 0.7-1.0 at the boundary with the top sublayer, the top sublayer is equal to 0.7-1 at the boundary with the lower sublayer, said value gradually reduces up to the value of y