Mass Spectrometry of Recoiled Ions for in-situ Surface Analysis: Status and Possiblities

Abstract

Format

This is a copy of the slides presented at the meeting but not formally written up for the volume.

Abstract

Mass Spectrometery of Recoiled Ions (MSRI) in combination with time of flight ion and neutral scattering spectrometery (INSS) have been used in a number of laboratories for monitoring and controlling surface elemental composition during thin film growth processing. Pulsed keV ion beams impinge a growing surface at grazing incidence and the recoiled elements and ions which are either scattered (INNS) or recoiled (MSRI) into a forward direction are measured by their time of flight between the surface and an ion detector positioned some tens of cm away. Surface compositions can be inferred by INSS from energy losses of the scattered neutrals or ions. MSRI enables qualitative mass spectrometry from the surface by time of flight reflectron mass spectrometry of the ionized directly recoiled elements.The limitations of these two techniques becomes apparent when trying to devise instrumentation which can provide even semi-quantitative surface analysis at time scales of a few seconds and precisions of a few ppm. The possibilities of alternative but related approaches to rapid surface analysis which may now be possible (given advances in laser and detection technology) will be suggested and discussed.