The application of the oxygen cluster primary ion beam to Secondary Ion Mass Spectrometry (SIMS) was studied to obtain improved profiling qualities. In order to evaluate the analytical potential of the oxygen cluster beams, the decay length (λ d ), surface transient width (w) and sensitivity measured with the O 3 + primary beam have been compared to O + and O 2 + data. The λ d of B + signal was determined by interface broadening of boron-doped amorphous-Si/Si substrate. Further, secondary ion yield transient width (w) was observed. It was found that the O 3 + primary beam gives the best depth resolution with excellent sensitivity among the three kinds of primary ions. Using the 8 keV O 3 + beam with incidence angle of 37°, λ d of 3.5 nm and w of 14 nm were observed. The results indicates that λ d is proportional to 1/n for primary beam of cluster size (n). This is in excellent agreement with Zalm-Vriezema model. Moreover, we show that w varies in proportion to the impact energy per atom.