High-resolution measurement by a high-T/sub c/ superconductor sampler

We measured a signal current waveform by using a high-T/sub c/ superconductor (HTS) sampler with a 1-ps delay between every sampling point. The maximum time differential obtained in the measured waveform was 12 /spl mu/A/ps with a 2.5-/spl mu/A current sensitivity at 25 K. This result guarantees that the sampler is able to measure current waveforms correctly when their maximum time differential is less than 12 /spl mu/A/ps. The superior temporal response was achieved by using high-speed single-flux-quantum pulses generated in the HTS circuit. A unique feature of the sampler is that it directly measures the current with picosecond and microampere resolutions. Measurement of current flowing through wiring in a semiconductor large-scale integrated circuits is a promising application for the HTS sampler.