Electrical Characteristics of Superconducting Ti Transition Edge Sensors

We have designed and fabricated superconducting Ti transition edge sensors (TES) with different microbridge lengths varying from 1 to 6 \(\upmu \)m. The current–voltage characteristics of the fabricated Ti TESs are measured at different bath temperatures using a commercial SQUID amplifier. The thermal conductance (G) is found to be about 300 pW/K for a 2.6-\(\upmu \)m-long device. In addition, the effective response time measured with a current pulse signal is about 3 \(\upmu \)s, and decreases with increasing the bias voltage because of negative electro-thermal feedback. The obtained electrical noise equivalent power from the measured current noise is about \(4 \times 10^{-17}\) W/Hz\(^{0.5}\), which is sufficiently low for TeSIA instrument.