TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The PN junction may be reverse-biased and generates a depletion region, and the sensitive region extends within the depletion region. The PN junction forms a diode or is formed by a bipolar transistor. The acceleration and gain regions extend adjacent to body surface, and the sensitive region extends beneath the acceleration and gain regions. The acceleration, gain and sensitive regions form an active region (12) laterally delimited by trenches (10) which are coated or filled with insulating material (23). The acceleration and gain regions are formed by a surface region of first conductivity type and adjacent to the body surface, and by a junction region of second conductivity type extending beneath the surface region and having a first doping level. The sensitive region has a second conductivity type and a second doping level which is lower than the first doping level.The semiconductor-material body beneath the sensitive region has the second conductivity type and a third doping level that is lower than the second doping level. The body is formed by a monocrystalline region of silicon-on-insulator substrate. A separation region (18) having second conductivity type and third doping level extends between the junction region and sensitive region. The surface region is adjacent and electrically connected to a first contact region (24) formed on top of body surface. Biasing regions (22) extend laterally and externally to the trenches, and are connected to second contact regions (25). The biasing regions have the second conductivity type and a fourth doping level that is higher than the second doping level.Preferred Process: The surface region is formed by implanting boron ions at an energy level of 5-50 keV and a dose of 1x1014 - 1x1016 atoms/cm2 to obtain a final doping level of 1x1019 - 1x1020 atoms/cm3 and a depth of 0.1-0.15 mum. The junction region is formed by implanting phosphorus or arsenic ions at an energy of 80-150 keV and a dose of 1x1014 - 1x1016 atoms/cm2 to obtain a final doping of 1x1019 - 1x1020 atoms/cm3 and a depth of 0.15-0.2 mum. The sensitive region is formed by implanting ions of rare earths at an energy of 0.5-2.5 MeV and a dose of 1x1012 - 1x1014 atoms/cm2 to obtain a peak final concentration of 1x1016 - 1x1018 atoms/cm3.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The semiconductor material is silicon, indium phosphide, or gallium arsenide. The sensitive region is doped with erbium, holmium, neodymium, or promethium.