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Extensive use has been made of the advantages ion implantation has to offer over standard processing for the fabrication of high performance n-channel MOS circuits. By combining an enhancement driver with a depletion load, the maximum switching speed of FET logic elements has been evaluated for self-aligned structures with various channel lengths and various degrees of substrate decoupling via device-to-substrate capacitances. An 11-stage ring-oscillator circuit is used for performance evaluation. Switching delays as small as 115 ps were obtained for such inverter stages built on 200 Ω×cm substrate material and having 1-μm channel length. Essential fabrication details and circuit behaviors are described.