Broadening effect in SIMS depth profiling, attributed to diffusion and segregation, was explored for In with O₂⁺ bombardment at low energies (180 eV-5 keV) and over a wide range of impact angles, from normal (0^o) to glancing incidence (70^o). The effect depended on the oxidation level of the oxide layer generated by the oxygen bombardment. The oxidation level was controled by the sputtering yield and the yields below 0.3 atoms/O₂⁺ enhanced the effect. At the yields above 0.3 atoms/O₂⁺, the atomic mixing strongly influenced on the effect. The use of glancing incidence reduced the effect. However, another unfavorable effect, i.e., the ripple formation was observed at glancing incidence. The “critical angles” were around 40^o. The bombardment at about 40^o is effective for more accurate depth profiling.