Deep defect levels and mechanical strain in Ge +-implanted silicon

Abstract

Electrically active defects and the deformation of the crystal lattice produced by Ge + ion implantation of silicon and their evolution during annealing have been investigated using deep-level transient spectroscopy and X-ray diffraction measurements. Three types of defect levels have been observed. In as-implanted samples and at low annealing temperatures (up to about 600°C) well-known vacancy-related defects levels are observed. At about 500°C levels at E c − 0.53 eV and E c − 0.28 eV, related to defect complexes containing Ge, show up and disappear at about 900–1000°C annealing. In addition, two less dominant defect levels at E c − 0.40 eV And E c − 0.15 eV are observed at high annealing temperatures (500–900°C). They are related to defects at the boundary between recrystallized regions and the rest of the crystal and are not specific for Ge. The annealing behaviour of the mechanical strain reflects the behaviour of vacancy related and Ge-related defects in silicon.