Improvement of hydrogen detection limit for quadruple SIMS tool

Hydrogen is an element of significant interest for semiconductor process; however it cannot be detected by many available elemental analysis techniques. Secondary ion mass spectrometry (SIMS) is one of the few techniques for the measurement of hydrogen amount and depth distribution. Among all kinds of SIMS tools, magnetic sector, quadrupole and time-of-flight, quadrupole SIMS instrument usually has lowest vacuum pressure and therefore should have better hydrogen detection limit. But high blast-through noise from mass 0 to mass 1 significantly affects the hydrogen detection limit. Various methods to improve hydrogen detection limit were investigated in this study. With field axis potential bias and higher mass edge measurement, hydrogen detection limit of quadrupole SIMS tool was improved by one order of magnitude to 2.2×1018 atoms/cm3.