Title :
Preparation of ramp-edge interface modified junctions for HTS SFQ circuits
Author :
Horibe, Masahiro ; Ito, Takuma ; Inagaki, Yukitoshi ; Matsuda, Gen-ichiro ; Fujimaki, Akira ; Hayakawa, Hisao
Author_Institution :
Dept. of Quantum Eng., Nagoya Univ., Japan
fDate :
3/1/2001 12:00:00 AM
Abstract :
We have studied the properties of ramp-edge interface modified Josephson junctions (IMJs) whose barriers are formed during the etching process and subsequent annealing process. We investigate the effect of process parameters on junction characteristics (Ic, Rn ) and obtain an empirical equation concerning their relationship. We select accelerating voltage (Vacc) and etching time (tetch) for the control of Ic of IMJs and set the target value of Ic at 4.2 K to 500 μA in this study. This target value can be realized by Vacc=500 V and tetch =20 min from our empirical equation. We prepare four different samples fabricated in the same conditions, and examine the reproducibility and controllability of Ic. The obtained Ics are very close to the target value, and the run-to-run spread is confined to about 150 μA. The reproducibility and controllability of Ic are improved compared to our previous data of junctions with artificial barriers
Keywords :
Josephson effect; annealing; barium compounds; critical currents; high-temperature superconductors; lanthanum compounds; process control; sputter etching; superconducting integrated circuits; superconducting junction devices; yttrium compounds; 20 min; 4.2 K; 500 V; 500 muA; HTS SFQ circuits; MgO; MgO substrate; PrGaO3-YBa1.95La0.05Cu3 O7; SrTiO3; SrTiO3 substrate; YBaLaCuO ramp-edge interface modified junctions; accelerating voltage; annealing process; critical current control; empirical equation; etching process; etching time; junction characteristics; process parameters; reproducibility; run-to-run spread; Acceleration; Annealing; Circuits; Controllability; Equations; Etching; Fabrication; High temperature superconductors; Reproducibility of results; Voltage;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
