Hydrogen depth profiling using SIMS—Problems and their solutions

Problems associated with trace hydrogen detection by SIMS are discussed. These include: (1) residual gas contamination, (2) primary ion beam contamination, (3) detection of stray H secondary ions, (4) instrumental background at low mass (for quadrupole instruments), and (5) matrix-related sensitivity artifacts. In depth-profiling a proton implanted silicon sample, H detection limits of 2 × 1018 at/cm3 could be obtained, but only when the partial pressure of H2O was reduced to 1 × 10−10 Torr (1.33 × 10−8 Pa). The importance of using cesium primary ion bombardment is also discussed, as well as the ability to detect both hydrogen and deuterium in the same analysis.