Reduction of artifacts in temperature programmed desorption measurements of field generated, real-life, powered samples

Abstract

Temperature programmed desorption (TPD) is a powerful surface analytical technique used for studies of adsorbate systems when background effects such as desorption from the mounting wires and/or the heater assembly can be minimized. Researchers often use TPD measurements to determine the desorption characteristics of field generated, real-life samples that have been prepared under ambient conditions. Since real-life samples are generated under ambient conditions, the potential for background effects is significantly enhanced. In many cases, background effects and their implications on data analysis are not considered. It will be demonstrated that background effects are very significant for real-life, field generated samples when traditional protocols are used for TPD measurements. We have devised a novel experimental protocol to reduce background effects during TPD measurements of field generated, real-life powdered samples. The novel experimental apparatus and procedures will be described. TPD spectra measured using the new protocol will be compared with spectra measured using traditional protocols.

Low temperature plasma for the preparation of crater walls for compositional depth profiling of thin inorganic multilayers

“…Low temperature plasma (LTP) is a dielectric barrier discharge (DBD) technique that generates a non‐thermal plasma in atmosphere, and has been used for ozone generation, polymer surface treatments, biological decontamination, and recently as a way to prepare crater walls for the indirect depth profiling of organic multilayers using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) . The use of LTP for indirect depth profiling showed many advantages over a traditional ToF‐SIMS molecular depth profile, where buried structures were easily resolved with high lateral magnification without the formation of ion bombardment artifacts such as chemical damage accumulation, polymer crosslinking, and topography generation that often results in degraded depth resolutions and broadening of interface widths .…”

“…The properties of the plasma can be altered relatively easily by changing the composition of the carrier gas; while pure argon or helium gas plasmas lead primarily to etching of organic molecules through chain‐scission and formation of volatile molecules, the addition of highly fluorinated molecules such as CF 4 or SF 6 into the carrier gas can lead to etching of metals through the formation of volatile fluorides . The ability to etch metals is particularly intriguing as it provides a way to prepare crater walls for the subsequent analysis with an imaging tool for compositional depth profiling of inorganic multilayer systems.…”