Fully ion-implanted normally-off-type JFET GaAs ICs were fabricated by selective ion implantation of Si directly onto a Cr-doped semi-insulating substrate for an n-active region and Zn for a p+-gate region with subsequent capless annealing in AsH3 ambient. A 15-stage ring oscillator, consisting of the DCFL logic gate with resistive load, exhibited a propagation delay time of 85 ps/gate with a power delay product of 34 fJ.