Abstract: A field effect semiconductor device that has particular use in limiting current in electric circuits over a very wide power range. In a preferred form, the device consists of a crystalline-material semiconductor wafer having multiple channels at one major surface thereof, the channels being separated by grooves formed along parallel crystallographic planes of the crystalline material. The wafer material forming each of the channels is lightly doped and each channel is bounded by flat walls, parallel to one another and formed by highly doping the wafer material with a dopant that is opposite in type to that of the channels. All said one major surface of the wafer is highly doped with the opposite-type dopant to that of the channels with the exception of ohmic-electric-contact regions of each channel, which regions are highly doped with the same-type dopant as that of the channels. All said one surface, except at the edge or edges thereof, is covered by a first conductive terminal.