Ion Implanted Silicon Bolometers Operating in the Temperature Range 0.1-4.2°K

Silicon bolometers have been obtained by phosphorous implantation on single crystal silicon substrates. These devices work like microcalorimeters. The wafer substrate acts as the energy absorber, while the implanted resistor is the temperature sensing element. For proper operation, the doping concentration of the thermistor is tailored near to the critical concentration of the metal insulator transition of the Si:P system. The optimum operating point is typically between 0.1 and 4.2K, depending on the specific application. In this work the basic physical principles of operation of thermal detectors are oulined, then the technology developed for the realization of high sensitivity, ion implanted thermistors is briefly discussed. Examples of applications of the device as molecular beam detector, alpha-particle or X-ray radiation detector is also presented