Characterization of optically active defects created by noble gas ion bombardment of silicon

Abstract

The modification in the G-line (969.5 meV) and the C-line (789.4 meV) photoluminescence (PL) intensities were studied as a function of the fluence, energy, and mass of the bombarding ions (He, Ne, Ar, and Kr). The intensities of the luminescent lines induced by 1 keV Ne bombardment were found to decrease with increasing dose after reaching a maximum at about 1×1012 ions/cm2. Considerable reductions in the intensities of the G- and C-lines were also recorded during bombardment using heavier noble gas ions and they have been attributed to the higher rates of nuclear energy deposition with increasing bombarding ion mass. The incident ion energy at which the PL intensities of the spectral lines reached their maximum values was found to be dependent on the ion mass and fluence. We have explained the decrease in PL intensities of the G-line and C-line to be due to the introduction of increased amounts of nonradiative recombination centers with increasing incident ion dose and mass. Further, the integral sum of defects induced during bombardment as a function of projected ion range and excitation depth of the Ar-ion laser has been used to qualitatively describe the decrease in the intensities of the two lines.