Novel Compact and High-Resolution Ion Backscattering Analysis System,Chiribas

ABSTRACTThe design and performance of CHIRIBAS(Compact and High-Resolution Ion Backscattering Analysis System) are presented. The system consists of a 60 kV duoplasmatron and unique energy analysis systems connected to a microcomputer. The 5–60 keV H, He, and He+ beams are backscattered to 180° and their energies are analyzed by a time-of-flight technique or with an electrostatic deflector combined with a position sensitive microchannel plate. The probing depth and depth resolution are estimated to be up to 50 nm and better than 0.5 nm, respectively. The computer-simulated spectrum analysis allows rapid and accurate determination of surface and interface structures such as depth profiles of elemental compositions and lattice defects. CHIRIBAS also makes it possible to measure excited state populations using Stark ionization for 5–10 keV H neutralized at the exit surface and thus provides the possibility to determine the energy and spatial distributions of the valence electrons extending outward from the top surface. The present article includes the beam parameters achieved and the preliminary data on reactive-ion etched Si surfaces.