Dose analysis of nitrogen plasma source ion implantation treatment of titanium alloys

Abstract

Dose analysis of plasma source ion implantation (PSII) treatment involves two issues: calculation of the delivered dose and measurement of the retained dose. This article discusses the delivered dose calculation method and the determination of constants used in this calculation, such as the secondary electron emission coefficient and average number of atoms per ion being implanted. Both can be measured experimentally at the University of Wisconsin PSII group. The retained dose is usually studied by Auger electron spectroscopy (AES). For nitrogen PSII treated titanium alloys, like all titanium nitrogen compounds, the chemical analysis by AES is complicated by two factors: (1) the Auger electron emission from nitrogen occurs at an energy that completely overlaps a transition from titanium; and (2) titanium oxide has a strong influence on the titanium transitions. In this study, a new technique that takes into account the influence of titanium oxide and solves the overlap problem has been developed to convert AES data to a concentration depth profile. A comparison of the concentration profile for nitrogen as observed in the AES data and calculated by the tamix code (computer simulation) shows good agreement.