In the past, oxide passivated silicon radiation detectors, used in nuclear physics research, have been mostly limited to sensitive depths less than 1mm, with cost limitations making the practical limit for large scale applications closer to 0.5 mm. This project will extend the useful sensitive depth of individual and segmented oxide passivated Si detectors to the 1-3 mm range and incorporate high value monolithic resistors on the same substrate. Phase I extended a previously developed technique for neutron transmutation doping to make very high resistivity <100> Si. It was also demonstrated that the flat band voltage is lower for <100> than for <111> for the same resistivity. Finally the proposed technique for improved surface passivation was shown to be feasible. In Phase II, the neutron transmutation doping will be combined with two new techniques for reducing the flat band voltage of the oxide passivation and for reducing channel conductance and surface recombination currents. Very high sheet resistivities on Si surfaces will be produced for the fabrication of monolithic high value resistors.
Commercial Applications and Other Benefits as described by the awardee: The availability to oxide passivated deep Si detectors will make an important contribution to radiation detection and spectroscopy application in many diverse areas ranging from particle physics research to industrial x-ray spectroscopy. A new technology for ultra-shallow junctions should be valuable for the next generation of <0.2ยต devices.
