Expansion of Neutron-Transmutation-Doped Silicon (NTD-Si) semiconductor productivity using research reactors (JRR-3, JRR-4 and JMTR)

Working Group for NTD Technology

Neutron-transmutation-doped silicon (NTD-Si) is regarded as a promising semiconductor for power device application. The demand of NTD-Si is expected to be raised significantly due to mass production of hybrid-cars in the near future. In order to meet the demand, we have investigated the expansion technology of the NTD-Si productivity in the research reactors of JRR-3, JRR-4 and JMTR. We have made out the following proposals. (1) In the JRR-3, the external cooling method should be preferentially developed to be twice the productivity of NTD-Si using a modified Si-irradiation facility, at the first step. At the next step, a full-automatic Si-irradiation facility should be installed to increase the NTD-Si productivity four-times. (2) In the JRR-4, the Si-irradiation facility, by which an Si ingot of 8- and 12-inch in diameter can be irradiated with neutrons, should be designed and installed around the reactor core tank. (3) In the JMTR, the Si-irradiation facilities for 8-inch and 6-inch diameter ingots should be developed for producing NTD-Si of approximately 30 ton/year. By realizing the modifications mentioned-above, the productivity of NTD-Si will increase to approximately 46 ton/year, that is about 10 times as great as the present one, and thus about a half of the present domestic demand of NTD-Si will be covered by processing utilization of the research reactors.Silicon carbide (SiC) semiconductors doped with the NTD technology are considered suitable for high power devices with superior performances to conventional Si-based devices. It is strongly recommended that R&D of SiC-NTD technology is performed in collaboration with industries and research institutes.