Ion beam sputtering - the effect of incident ion energy on atomic mixing in subsurface layers

Abstract

Abstract Secondary ion mass spectrometric methods were used to study the effect of incident ion energy on atomic mixing in subsurface layers. A Ta2O5 film containing a 50 A 3lP-rich layer 230 A below the surface was depth profiled for phosphorus using normal incidence 160 primary particles of various energies (1.75 to 18.5 keV). A pronounced energy effect was observed in the widths of 31P profiles generated by >4 keV 16O. For 18.5 keV 16O, the observed profile contained two distinct components-the 31P-rich layer and the 31P recoil distribution. This later condition, prevails when the peak of the incident ion damage distribution occurs at a depth which equal or exceeds the distance from the surface to the 31P-rich layer. The desirable primary ion beam energy for characterizing the true elemental distribution is dictated by the shape and location of the layer to be profited. In most instances, a low energy beam is preferred.