Sub-10 ps high-gain direct coupled Josephson logic gate

A cascade chain of high-gain direct coupled logic gates with a 25×20 μm2 gate size was designed and fabricated using Pb-alloy Josephson technology with Josephson junctions of 3 μm diameter and 2 μm line-width resistors. Logic delays as low as 9 ps and power-delay products as small as 30 aJ were experimentally obtained.