Effect of irradiation with 15-MeV protons on the compensation of Ge〈Sb〉 conductivity

Abstract

The processes of the compensation of n-type conductivity in germanium irradiated with 15-MeV protons are investigated. Irradiation results in a considerable reduction in the density of shallow donor states of Group-V atoms. The rate of removal of shallow donor states due to the interaction between impurity atoms and radiation-induced intrinsic point defects is ~215 cm^–1. The majority of secondary defects produced under proton irradiation are electrically neutral in an n-type material. Radiation-induced acceptors are of little importance in this case. Numerical modeling is performed, and the distribution of the energy transferred to recoil atoms is obtained. Two energy intervals are considered in the analysis of distribution histograms. At low energies, individual Frenkel pairs with closely spaced components are produced. The energy of recoil atoms in the second energy region is sufficient to induce a displacement cascade. Nanoscopic regions with high densities of intrinsic point defects and their complexes with dopant atoms are formed in such cascades. A model of the generation of intrinsic defects in germanium under proton irradiation is discussed.