SIMS measurement of hydrogen and deuterium detection limits in silicon: Comparison of different SIMS instrumentation

Abstract

Hydrogen is the most abundant element in the universe, but it cannot be detected by many analytical techniques. This element is used to improve interface quality and reduce the impact of defects in silicon technology. Knowledge of the amount and distribution of hydrogen is of significant interest for many technologies, such as ZnO and glass manufacturing. Secondary ion mass spectrometry (SIMS) can provide analysis for hydrogen and the isotopes deuterium and tritium. Lower instrument vacuum will improve the hydrogen detection limit. Vacuum conditions can be optimized by methods such as overnight pumping of samples and sample holder heating. Adsorption of hydrogen from the vacuum environment during analysis can be minimized with use of high sputtering rate. The species monitored may be atomic or molecular, such as H- or Cs2H+. The latter species provides a practical means for hydrogen profiling in dielectric films in magnetic sector instruments with conventional charge compensation. It is of interest to compare the detection limit that can be obtained for various SIMS instrument configurations under typical operating conditions. Time of flight, magnetic sector, and quadrupole analyzers were used to analyze hydrogen and deuterium ion implanted silicon. The detection limits varied for the different analyzers used and were in the 1018-1019 atoms/cm3 range for hydrogen and as low as 1016 atoms/cm3 for deuterium.