A gigabit MOS logic circuit with buried channel MOSFET's

An MOS frequency divider operating with gigabit clock rate has been realized to show the potential of MOS logic circuits for high-speed applications. The divider was constructed with buried channel MOSFET's as the basic elements. A master-slave flip-flop that was constructed with the enhancement/depletion type NAND gates was used for the divider. The basic gates were designed using full 1 micron patterning rules. For the fabrication of these very fine circuits, photomasks made by an electron-beam system were applied and sputter etching was employed to form fine patterns such as the polysilicon gate and contact holes. The maximum counting frequency of 1.64 GHz and the shortest propagation delay time of 72.5 ps/gate with a fundamental gate were obtained.