Material characterization by means of positron annihilation

Positron annihilation is a nondestructive technique for investigating vacancy-type defects in solids. When a positron is implanted into materials, it annihilates with an electron and emits two 511 keV γ quanta. By measuring the energy spectra of the annihilation γ rays and the positron lifetimes, one can detect defects such as monovancancies and open pores. The defect species and their concentrations can be estimated from a comparison between the Doppler broadening spectra and the positron lifetime obtained through the experiments and those calculated using first-principles calculation. In the present paper, we report the detection of vacancy-fluorine complexes in F-implanted Si and the characterization of low-k materials buried in a device structure. (author)