Hydrogen-induced formation of defects nanocluster in crystalline silicon

Influence of hydrogen impurity on the formation of vacancies nanocluster in silicon has been studied by means of electron paramagnetic resonance (EPR) along with unaxial-stress experiments and electrical measurements. Hydrogen was incorporated mainly by proton implantation at room temperature. We demonstrate that hydrogen implantation in silicon leads to strongly coordinated formation of vacancies cluster during subsequent annealing of sample at 500–700 K. The structure of the defect represents a ring of the six vacancies situated exactly in (111) plane. A pair of hydrogen atoms involved in the defect structure is responsible for the stability, paramagnetic (S=1) state and high symmetry (D3d) of the nanocluster. At definite conditions (ion dose, heat treatment), simultaneously with vacancies cluster, nanoclusters of self-interstitial are created, which can be a source of shallow electrons and can form silicon fragments with high conductivity. The properties of vacancies cluster along with ion beam technology for their creation suggest that they can be considered as an island isolating in a multi-layer structures.