Performance and Applications of Passivated Ion-Implanted Silicon Detectors

Planar process has been applied to the fabrication of nuclear radiation detectors. Combining techniques of oxide passivation, photoengraving and ion implantation any desired detector shape can be made with small tolerances in geometrical and electrical properties. Extremely low reverse currents are obtained (less than 1 nA cm-2/100 μm at room temperature) and therefore excellent energy resolutions : 10.6 keV for 5.486 MeV alphas, 1.55 keV for 122 keV gamma-rays with 25 mm2 area detectors, 300 μm thick. The detectors are capable to be backed at 200° C under vacuum. Due to the fact that arrangements of many detectors on one wafer can be made, new possibilities open up, especially for particle localization in high energy physics. Planar versions of 200, 50 and 20 μm pitch parallel microstrip detectors have been realized. Results obtained using a beam of 10 GeV/c pions are presented. Close mounting of several detectors allows the construction of telescopes used as live target in high energy physics experiments.