Radiation damages induced in n-type silicon by ions and neutrons.

In this paper new measurements of physical properties of high resistivity s ilicon used in high-energy detectors are presented. The obtained data contr ibute to the understanding of the causes which, produce damage of the elect ronic characteristics of the detection systems under neutrons and ionized p articles radiation. Hall effect coefficient (R-H) and resistivity (rho) mea surements as it function of temperature (T) for non-irradiated and irradiat ed by neutrons and Kr ions, were performed. The measurements of Hall coeffi cient and resistivity of samples non-irradiated and irradiated at low neutr on fluences (Phi less than or equal to 19.9x10(10) n/cm(2)) have shown that the obtained characteristics R-H(T) and rho(T) are practically the same as those known for silicon single crystal, while for Kr differences appear ev en at the lowest fluence (Phi=7.5x10(8) Kr/cm(2)). Increasing the irradiati on, important changes in the physical properties were observed. The resisti vity increases with increasing Phi up to a value of the order of rho simila r to 10(5) Omega cm, for both neutron and Kr irradiations. The values of RH increase with increasing Phi and change the sign from negative to positive . The variation of values of RH and rho as a function of Phi for neutrons a nd Kr ions is similar, but the characteristics R-H(Phi) and rho(Phi) are sh ifted. The measurements for neutrons irradiated samples show that larger va lues of neutron fluence are needed to produce the same damage as the Kr ion s. The results obtained in this paper may explain the influence of irradiation on the physical properties of silicon and, as a consequence, on the charac teristics of the detectors.