Characterization of Doped Silicon Thermometers for Very High Sensitivity Cryogenic Bolometers

Understanding the origin and early evolution of stars is one of the fundamental objectives of astronomy. This can be possible with observations made from space in the mid- to far-infrared and millimeter-wave part of the spectrum which require detectors with very high sensitivity. In the framework of the SPICA project and the course of developing cooled semiconductor bolometers for sub-millimeter-wave detection, typically 100 μm ≤ λ ≤ 1.5 mm, we have investigated several thermometers based on doped silicon Si:P,B. We observed an important dependence of the Si:P,B resistance to the doping densities and found potential thermometers for cryogenic detections at very low temperatures (50 mK < T < 100 mK). In addition, numerical simulations allowed us to study the thermoelectrical behavior of the potential detectors and predict a clear enhancement of the detector performances.