| AVS 58th Annual International Symposium and Exhibition | |
| Applied Surface Science Division | Monday Sessions |
| Session AS-MoA |
| Session: | Quantitative Surface Chemical Analysis and Technique Development - Part II |
| Presenter: | Mark Engelhard, Pacific Northwest National Laboratory |
| Authors: | M.H. Engelhard, Pacific Northwest National Laboratory D.R. Baer, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
The method and procedures used by many researchers doing sputter depth profiling has evolved from the experience of many researchers using several generations of sputter ion guns. Often considerable instrument time is used to establish the sputtering rate for specific instrument configuration and operating conditions at the time of analysis. We have conducted an inter-laboratory “round robin” study help identify the types of variations actually observed in sputtering systems in use today to help determine the time frame for which calibration may be needed, depending on the type of information required by the analysis. The depth of thin layers was identified as a major information need in surface analysis by surveys done for E42 and ISO TC201. This “round robin” was undertaken as an ASTM International Interlaboratory Study (ILS 229) The results obtained from this study will be used to determine a required frequency of ion gun sputter rate calibration and for the development of a guide or standard.
In this poster we present results obtained from seven ILS-229 participants. Each participant was sent a package containing 7 SiO2 coupons with known thickness measured using a J. A. Woollam Co. α-SE Spectroscopic Ellipsometer. The participants were asked to perform 5 depth profiles using identical ion gun settings at different time intervals: Immediately after turning the ion gun filament (minimal warm up), after a 60 minutes filament warm up period (typical warm up), at the end of the day (filament on all day), the following day (typical filament warm up of 60 min.), and after one week (typical filament warm up of 60 min.) The sputter rates were determined from a plot of the Si and O intensity as a function of sputter time. The time needed to sputter through the entire SiO2 layer (when the O signal drops to 50% of the plateau value) is identified as the sputter time. The sputter time tsp is determined using ASTM Standard Practice E 1636-04 “Analytically Describing Sputter-Profile and Linescan Profile data by an Extended Logistic Function”. The results demonstrate both the excellent consistency of sputter conditions for many ion gun systems, but also the need to have a process to actually determine the stability of a specific ion gun system and configuration.