SINGLE FLUX QUANTUM ELEMENTS BASED ON A SINGLE-LAYER OF A HIGH-T-C SUPERCONDUCTOR

We have designed, fabricated and successfully tested three SFQ element s: a toggle flip-flop, a SFQ voltage amplifier, and an RS-flip-flop, T he design uses a single superconducting layer and it is optimized by r epeated computer simulations and repeated inductance calculations. The inductances are made as narrow slits of 0.5 mu m width. Their values are calculated numerically taking into account material parameters der ived from experiment, The YBCO junctions are either of step edge type an LaAlO3 substrates or located on two closely spaced bi-crystal grain boundaries on a novel YSZ tri-crystal substrate, Carbon masks were us ed to form steps on LaAlO3 substrates and for the YBCO patterning. Vol tage amplifier shows operation up to 60K, and both flip-flops were obs erved to operate at temperatures up to 30K with parameters close to th e simulated values, The operation frequency of a T-flip-flop cell of a bout 150 GHz was achieved and a new measurement technique of the margi ns of an RS trigger is suggested.