The influence of H impurity upon the formation of vacancy nanoclusters in Si was studied by means of electron paramagnetic resonance, plus unaxial-stress experiments and electrical measurements. The H was incorporated mainly by proton implantation at room temperature. It was demonstrated that H implantation led to the strongly coordinated formation of vacancy clusters during subsequent annealing (500 to 700K). The structure of the defect was that of a ring of 6 vacancies situated exactly in the (111) plane. A pair of H atoms involved in the defect structure was responsible for the stability, paramagnetic (S = 1) state and high symmetry (D3d) of the nano-cluster. Under given conditions of ion dose and heat treatment, and in addition to vacancy clusters, nano-clusters of self-interstitials were created. These could be a source of shallow electrons and could form Si fragments having a high conductivity. The properties of vacancy clusters, together with the ion beam technology for their creation, suggested that they could be considered to be an island isolated in a multi-layer structure.

Hydrogen-Induced Formation of Defects Nanocluster in Crystalline Silicon. Y.V.Gorelkinskii, K.A.Abdullin, B.N.Mukashev: Materials Science and Engineering C, 2002, 19[1-2], 397-400