A Review of Transmutation Doping in Silicon

The neutron transmutation doping (NTD) process in silicon is based upon nuclear reactor thermal neutron irradiation which induces the neutron capture reaction 30Si (n,γ) 31Si → 31P + ß-. The transmutation product, phosphorus, becomes electrically active after suitable annealing of the accompanying radiation damage which is caused by a number of displacement processes. Because of the superior doping homogeneity which results from the NTD process, a number of device applications have evolved resulting in a significant fraction of the world's float zone being neutron doped. This paper will present a review of basic research and production techniques which have evolved at MURR as a result of work associated with this new radiation effects technology.