Electrical and back-scattering studies of thermally annealed gallium implanted silicon

Abstract

Abstract Dopant distribution, electrical activity and damage annealing of high-dose (∼5 × 1015 cm2) Ga-implanted silicon samples annealed by conventional thermal annealing have been studied by alpha particle back-scattering, differential Hall effect and ellipsometry measurements. Back-scattering spectra show that there is no long tail of Ga atoms in the as-implanted samples. Upon annealing these samples the damaged amorphous layer recrystallizes at about 570°C by solid phase epitaxy. During the epitaxial regrowth the dopant atom distribution seems to be modified. Further, very high levels of electrical activaton of Ga-atoms (∼3 × 1020 cm−3), much higher than the maximum solubility limit of Ga in Si (4.5 × 1019 cm−3), is achieved by thermal annealing of the sample at ∼570°C. This is comparable to the doping achieved by laser annealing of the Ga implanted Si. All the above three measurements show that there is residual damage in the high dose (≳1015cm−2) implanted samples after the recrystallization at abou...