Retargeting RSFQ cells to a submicron fabrication process

There is a desire to move current state-of-the-art niobium Josephson IC fab rication processes (similar to3 mum) to smaller sub-micron linewidths in or der to realize a decrease in gate size and increase in both speed and packi ng density. However, cost and time dictates that a way be found to reuse th e existing RSFQ gate/cell development that has been done at the 3-mum level . Cell retargeting is the process of migrating existing designs to a new te chnology, with the effort focused on the maximum reuse of existing material . We have investigated a number of issues critical to this process, includi ng both the physical and electrical aspects. Comments are made on methodolo gies for RSFQ cell retargeting with respect to existing reduced-linewidth J J fabrication processes. Experimental demonstrations are shown for retarget ed RSFQ static digital frequency dividers (toggle flip-flops) operating at 220 GHz, 240 GHz, and 395 GHz.