130 likes | 258 Views
SIMS-EDX system for a standard-free analysis Yu. Kudriavtsev , R.Asomoza Sección Electrónica del Estado Solido, Departamento Ingeniería Eléctrica, CINVESTAV-IPN, Av. IPN #2508, México, DF 07360, México yuriyk@cinvestav.mx. Introduction
E N D
SIMS-EDX system for a standard-free analysis Yu. Kudriavtsev, R.Asomoza Sección Electrónica del Estado Solido, Departamento Ingeniería Eléctrica, CINVESTAV-IPN, Av. IPN #2508, México, DF 07360, México yuriyk@cinvestav.mx
Introduction SIMS as any other technique has advantage as well as weak points. The most important disadvantage is poor quantification of SIMS data: by using implanted standards quantification can be done with an experimental error of around ±20%. SIMS analysis of main elements (the concentration range of 1%-100%) cannot be quantified by SIMS using implanted standards; a special calibration procedure should be performed, because of non-linear dependence between concentration of the element of interest and experimental secondary ion current, monitored for it. Energy dispersive X-ray spectroscopy ideally complements SIMS, because of standard free quantitative analysis of most of the elements with the concentration from 0.01 atomic % to 100 atomic %.
General idea: Utilize an Electron Gun of any SIMS instrument, used typically for charge compensation, to excite characteristic X-Ray emission from analyzed sample to realize Energy Dispersive X-ray spectroscopy method with the SIMS instrument.
Installation of EDD at ims-6f instrument Si crystal of EDD Primary ion trap EDX detector: Exterior view
A modified Strip: the closed window protect EDD in the SIMS mode
Application of EDX-SIMS instrument: • I. Semiconductors • Quantitative analysis of solid solutions: bulk, thick films, thin films. See Poster Section: Tue-pos-43 • 2. Calibration of SIMS (RSFs) for main element analysis in complex materials. • 3. Shallow junction analysis (LEXES “inside“). • II. Metals and alloys: • Quantitative analysis of bulk, thick films and thin films. • III. Glass (including natural), ceramics, minerals, etc. • Quantitative analysis of bulk, thick films and thin films. X-ray spectrum of obsidian
Two different strategies: • Perform a quantification of main elements by EDX , then analyze dopants and contamination by SIMS MBE grown 1 micron epi-layer of Al0.2Ga0.8N: EDX spectrum and SIMS depth profile
EDX spectrum and found composition of Ti allow Fig. RSFs as a function of Ionization potential of element. Points show experimental RSFs, found by SIMS with using of EDX data.
Table 1 Composition of Ti allow, defined by EDX/SIMS in comparison with Certificate of the provider. * Rose rows corresponds to elements used for SIMS calibration.
Conclusions: • EDX technique ideally complements SIMS for a quantitative analysis of complex materials. • Any SIMS instrument, equipped by an Electron Gun, can be “modified” to perform EDX analysis. • Energy of primary electron beam can be varied from 0 to 10keV, this means we can vary thickness of the analyzed layer from several microns down to a hundred nanometers. • Standard-free analysis in the “full” range of concentration: from 100 atomic % down to 10-7 atomic %, can be realized with a reasonable accuracy. THANK YOU FOR YOUR ATTENTION!