Progress Toward Transition Edge Sensor Arrays With On-Chip Thermal Stabilization

Electrothermal feedback in a transition edge sensor (TES) suppresses thermal fluctuations in the TES and well-thermally coupled regions in proximity. We have designed a heavily metallized, leg-isolated membrane with a TES which serves as a thermal isolation stage that can be lithographically integrated with other devices, for example, a suitably designed TES detector. Through modeling, fabrication, and test of prototype devices, we plan to examine the utility of stabilizing this guard stage to limit low frequency variability in the sensor response. In one implementation, a leg-isolated TES bolometer of higher superconducting transition temperature (T_c) is encircled by a second membrane region which is metallized and thermally stabilized by a second, lower-T_c TES. We present fabrication results on the dual-T_c device and explore varied heat capacity of the thermal stability stage in the single-pixel design. We then evaluate the use of this stage for multiple pixel arrangements and investigate the criteria for stabilizing such a device.