Ultra-fast (0.5- mu m) CMOS circuits in fully depleted SOI films

CMOS dual-modulus, divide by 128/129, prescaler circuits were built in thin Si films on SIMOX (separation by implantation of oxygen) wafers. They operated at 6.2 GHz, which is 50% faster than control circuits built in bulk Si. Detailed electrical characterization of individual n- and p-channel transistors was performed. The capacitances for the n and p diodes were also measured. Using these data in circuit simulations, it was determined that the gain in speed was primarily due to the decrease in the parasitic capacitances, in particular that of the source/drain junctions. Also measured were the ring-oscillator delay times, with a minimum delay per stage of 34 ps. >