High-T-c SQUIDs on silicon substrates

We have developed high-T-c SQUIDs based on Josephson step-edge junctions on silicon substrates. The SQUIDs show a transfer function up to 150 mu V/Phi(0) and a white noise of 10(-5)Phi(0)/Hz(1/2) 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.