Application of NTD Silicon for Radiation Detector of Surface Barrier Type

N-type extrinsic silicons higher than 10 kΩ-cm were produced from ultra-high pure P-type silicons by the neutron transmutation doping technique. Materials produced by the method has properties in dopant homogeneity and controllability better than conventionally doped ones. This has enabled us to fabricate a high performance detector with a large depletion depth. However, some problems were pointed out as to reverse Current-voltage characteristics, i. e., a reverse current level was so high to use the detector at room temperature. In order to improve this, a study of starting materials, neutron irradiation and annealing conditions are carried out. Significant improvements in detector performance have been obtained by using a material which is annealed at the temperature of 800°C for 10 minutes in an infrared lamp furnace.