Electrophysical properties of silicon doped by palladium-103 isotope

The work is devoted to study of radiation physical processes taking place in Si under nuclear transmutation, Identification and determination of defects microstructure and homogeneities and their distribution, study of interactions of nuclear-transformed phosphorus isotopes with palladium atoms, and its effect on crystal properties. For examination monocrystalline silicon of n- and p-type conductivity with specific resistance from 1 to 40 Ω·cm, dislocation density ∼104 cm-2 and oxygen content ∼1017 cm-3 has been applied. Doping of silicon plates by examined admixture has been carried out by thermal diffusion method within temperature range 1000-1250 deg. C for 0.5- 5 h. Irradiation of doped silicon was conducted by reactor neutron fluences 5·1018- 5·1019 cm-2 with subsequent annealing at 1000 deg. C for 30 min. Efficiency of mixture centers formation in silicon, effect of concentration of formed mixture-defect centers on electro-physical, photoelectric and recombination parameters of doped silicon and revealing of type and state of generated defects have been controlled by electric, volume and X-ray fluorescent methods. On the base of spectroscopic researches it is shown, that in silicon forbidden zone after Pd diffusion in DLTS spectra peaks related with acceptor (Ec-0.18 and Ev+0.34 eV) levels, and peak responsible for level Ev+0.32 eV of donor character caused by palladium impurity. It is shown, that irradiation of doped silicon samples by neutrons lead to nuclear transmutation of 102Pd, 104Pd in 103Pd isotopes in the crystal volume with following electron capture in stable isotope 103mRh