Biepitaxial Josephson junctions and SuFET technology for the preparation of HTS-JoFETs

K. Petersen; A. Walkenhorst; C. Stölzel; W. Wilkens; C. Krimmer; J. Söllner; H.W. Grueninger; R. Fischer; M. Schmitt; T. Becherer; H. Adrian

doi:doi:10.1051/jp4:1994633

Issue		J. Phys. IV France Volume 04, Number C6, Juin 1994 WOLTE 1 Proceedings of the First European Workshop on Low Temperature Electronics


Page(s)		C6-205 - C6-210
DOI		https://doi.org/10.1051/jp4:1994633

WOLTE 1
Proceedings of the First European Workshop on Low Temperature Electronics

J. Phys. IV France 04 (1994) C6-205-C6-210
DOI: 10.1051/jp4:1994633

Biepitaxial Josephson junctions and SuFET technology for the preparation of HTS-JoFETs

K. Petersen^{1, 2}, A. Walkenhorst², C. Stölzel^{1, 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

Abstract
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 J_c ≈ 10⁴ A/cm² and an I_cR_N-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 YB_a2Cu₃O_7-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 I_cR_N-product remains still in the typical range. The insulating properties are degraded compared to SuFETs.