Ion extraction from insulating fibers in ToF-SIMS

Extraction of ions in a triple focusing time-of-flight secondary ion mass spectroscopy system is studied as a function of substrate potential with samples consisting of insulating dielectric fibers mounted on a metallic substrate. It is determined that ions extracted from the surfaces of the dielectric require, in general, a higher substrate potential than those extracted from the surface of the metallic substrate. Results are explained in terms of the electrostatic potential distribution in the extraction region and the dielectric properties of the fibers.