Research On Circuit Simulation And Device Characterization Of Transition Edge Sensors

Superconducting transition edge sensors (TES) are being developed quickly in var-ious areas because of their number-resolving capabilities, high detection efficiency and negligible background dark count. As the scale of TES circuits grows, we need power-ful and reliable tools to support the design and research of TES sensors. Unfortunately, sophisticated electronic design automation (EDA) tools that can support the simulation and design of large-scale TES circuits are presently unavailable. An important reason for this deficiency is the lack of reliable TES device models that can be integrated in existing EDA tools to predict the behavior of TES circuits accurately.In this thesis, we solve this challenge by develop reliable TES models and inte-grated them in EDA tools to simulate the behavior of TES circuits. To model the highly nonlinear TES device, we use the two-fluid theory as the physics basis to describe its behavior. We choose the polynomial controlled source supported in most SPICE circuit simulators to model the effective TES resistance. We also develop a TES IV relation model which is more widely applicable. Both models are rely on only device parame-ters that have clear physical meaning and can be measured easily.We integrated our device models in powerful EDA tools such as CADENCE and OrCAD, and perform circuit simulations based on them. We find good agreemen-t between the simulations and publish experiment data which suggests that our device models based on the two-fluid theory can be used to predict the behavior of TES cir-cuits reliably. By running circuit simulations, we also discuss peculiar behavior of TES and the optimization of TES circuits. Finally, we describe our experimental work to characterize TES devices based on Al/Ti bilayer.