Field effect semiconductor device, esp. MESFET

摘要

The field effect semiconductor device has: (a) a first semiconductor layer (22) formed on a semi-insulating semiconductor substrate (21), bearing a control electrode (25) between opposite first and second electrodes (26,27); and (b) a depletion layer-forming system (40) between the control electrode (25) and the first or second electrode (26,27) in order to form, in the system, a depletion layer with an end lying nearer the substrate (21) than does an end of a depletion layer formed in the first semiconductor layer (22) by the control electrode (25). Also claimed are: (i) similar devices in which the depletion layer-forming system is replaced by other arrangements; and (ii) a similar device which omits the depletion layer-forming system and which has heterojunction-forming second and third semiconductor layers, the first and third layers pref. being of GaAs and the second layer pref. being of AlGaAs.