The Use of SIMS for Semiconductor Processing Technology: The Influence of Oxygen at Depth Profiling

Secondary ion mass spectrometry (SIMS) is one of the most powerful characterization methods in semiconductor processing technology. In SIMS, the presence of oxygen has been found to influence the intensities of the secondary ions emitted by the material under study, and therefore it is important to take the effect of oxygen into consideration. The following experimental facts are known. 1) The intensity of the secondary ion emitted from the surface or the interface of multilayer samples increases abnormally in the presence of oxygen (oxide). 2) When O₂+ or 0- is used as primary ion beam, it is difficult to determine fully the identity of the upper most surface layer (~200A), because the concentration of oxygen implanted in the surface increases continuously.