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Modification of Physical Characteristics of Materials

Production of radiation-doped silicon

Production of radiation-doped silicon

Of the current activities at the LVR-15 reactor in this field the most important is the production of radiation-doped silicon.

For the needs of the electrotechnical industry it is possible in the reactor to prepare silicon with a very high quotient of free electrons, which means with a low resistance, i.e. NTD Si (Neutron Transmutation Doped Silicon). NTD Si is used to manufacture mostly high-tension and high load components (for this type of component the use of NTD Si is essential).

Monocrystals of silicon

Silicon monocrystal

Super clean Si monocrystals are irradiated. Through the capture of a hot neutron by the nucleus of 30Si, 31Si is created, which with a half-life of 2.6 h changes to stable nucleus 31P, thus releasing an electron. 31P in semiconductor material functions as a donor. The advantage of this method of silicon doping is high donor homogeneity throughout the whole volume of the monocrystal.

In the LVR-15 reactor, technological equipment is in operation which allows the irradiation of silicon monocrystals to and average of 3” diameter. The production and installation is in progress of more rotating irradiation channels including the essential starter and other related apparatus for larger monocrystals of up to 4” diameter. After its launch an increase in production capacity is expected of up to 6 tonnes of silicon per year.