A method for neutron transmutation doping of silicon in research reactors

The irradiation of silicon for neutron transmutation doping (NTD) has become an important item in the industrial utilization of research reactors. This utilization is in fact an important technique in the electronic industry as it is used in the production of thyristors, diodes, and integrated circuits. This paper presents a method for silicon doping by irradiation in research reactors. The proposed method justifies the required homogeneity of phosphorus doped atoms and results in obtaining a final product with the specified homogeneous electrical resistivity. The method does not require a mechanism for rotating the silicon ingots during irradiation, and does not require the introduction of absorber material to flatten the neutron flux in the longitudinal direction of irradiated samples. The present work introduces also a method for optimization of the activation condition based on the use of a partial graphite reflector surrounding the irradiation channels for NTD of silicon in the reactor.