n-channel ion-implanted enhancement/depletion FET circuit and fabrication technology

n-channel enhancement/depletion technology and circuits are described. The threshold voltage adjustment to form the enhancement- and depletion-mode devices are achieved by ion implantation. This allows optimization of the performance and circuit density. The calculated and experimentally observed speed-power product is 10 pJ/pF with a single +5-V power supply. Inversion of the field region on the high resistivity p-type substrate is completely eliminated by the use of an implanted field shield.