High-Tc SQUIDs on Silicon Substrates

We have developed high-Tc SQUIDs based on Josephson step-edge junctions on silicon substrates. The SQUIDs show a transfer function up to 150µV/Φ0 and a white noise of 10-5Φ0/Hz at 50 K. During the last three years extensive investigations of the growth of YBCO, buffer and passivation layers as well as step-preparation and patterning processes were necessary to find a standard preparation process comparable to the preparation of Josephson step-edge junctions on classical substrates. In this paper we give an overview on the technical solutions based on the laser deposition of YBCO / buffer multilayer systems and we discuss Josephson junction and SQUID properties depending on different device preparation processes