SILICON THERMAL DETECTORS FOR SINGLE QUANTA OF RADIATION - FABRICATION, STATISTICAL FLUCTUATIONS OF PHONONS, PHYSICAL-PROPERTIES AND OPERATION

Fabrication of a thermal detector designed for high resolution spectro scopy of low-energy radiation is described. Details of the micromachin ing of pure silicon are given including the etching of the 0.1 mm3 abs orber and the doping process to obtain the temperature sensing thermis tor which is an integrated part of the absorber. The cryogenic system, the signal processing at working temperatures around 50 mK and the da ta acquisition system are discussed. Theoretical aspects of the intrin sic resolving power are presented. The relation between the intrinsic detector resolution and particle energy at different working temperatu res is derived. Measured resistance vs temperature is shown for thermi stors made with different dopings on wafers with different initial waf er resistivity. The influence of the initial wafer purity on the R-T c haracteristic curves is discussed. The optimal implantation dose was d etermined for thermistors implanted in high purity wafers.