Properties of secondary particles for ion beam sputtering of silicon using low-energy oxygen ions

The properties of secondary particles for sputtering silicon with primary low-energy oxygen ions were investigated with dependence on the primary ion energy E-ion and geometric parameters (ion incidence angle, polar emission angle, and scattering angle). The mass and energy distributions of the secondary particles were measured by energy-selective mass spectrometry. The experimental results were compared with simulations using the Monte Carlo code sdtrimsp and with calculations based on a simple elastic binary collision model. The main secondary ion species were found to be O+, O-2(+), Si+, and SiO+. Their energy distribution functions depend on the primary ion energy E-ion and the scattering angle gamma. For O+, Si+, and SiO+ ions, a decreasing scattering angle gamma or an increasing primary ion energy E-ion leads to a pronounced feature in the high-energy part of the distributions. The energy distributions of the secondary O-2(+) ions show hardly any changes with regard to the primary ion energy or the scattering angle gamma. In the case of the O+ ions, the energy distribution appears to reflect several direct scattering channels, which could be associated with the primary ion energy E-ion, and half of the ion energy E-ion/2. The present experimental results are compared with previous investigations for the sputtering of Si with the noble gas ions, such as Ne+, Ar+, and Xe+. Published under license by AVS.