Proceedings of the First European Workshop on Low Temperature Electronics
J. Phys. IV France 04 (1994) C6-205-C6-210
Biepitaxial Josephson junctions and SuFET technology for the preparation of HTS-JoFETsK. Petersen1, 2, A. Walkenhorst2, C. Stölzel1, 2, W. Wilkens1, C. Krimmer1, J. Söllner1, H.W. Grueninger1, R. Fischer1, M. Schmitt2, T. Becherer2 and H. Adrian2
1 Daimler-Benz Forschungsinstitut, Goldsteinstr. 235, 60528 Frankfurt/Main, Germany
2 Inst. f. Festk., Techn. Hochschule Darmstadt, Hochschulstr. 8, 64289 Darmstadt, Germany
Biepitaxial Josephson junctions and superconducting field effect transistors (SuFET) were fabricated in order to combine both techniques to a Josephson junction field effect transistor (JoFET). The Josephson junctions show RSJ-like behaviour. At 30 K a critical current density of Jc ≈ 104 A/cm2 and an IcRN-product of 0.1 mV were obtained. The oscillation of Shapiro steps with applied microwave field can be well fitted by the RSJ-model. SuFETs with CeO2 as dielectric show, for fixed charge transfer, results comparable to SrTiO3-based SuFETs. The downset of the resistive transition of a six-unit-cells thick YBa2Cu3O7-δ layer is 44 K and the largest field effect obtained so far is 1.5 %. Prelimary results on JoFETs show a drastic change in the critical current density and in the specific junction resistance, however the IcRN-product remains still in the typical range. The insulating properties are degraded compared to SuFETs.
© EDP Sciences 1994