Positive secondary-ion mass spectrometric study of silicon nitride films on Si and GaAs with a cesium ion source

The detection of positive secondary ions, as opposed to the conventional negative-ion detection, in conjunction with the use of a cesium primary-ion source was studied with a Cameca IMS-3F ion microscope. One advantage of this technique is that, unlike the detection of negative ions, charging of an insulating surface can be avoided. Plasma-enhanced chemical-vapor-deposited silicon nitrides on Si and GaAs were used as examples to demonstrate the usefulness of the technique. The distributions of species such as H, C, O, F, Al, Si, SiN, Ga, and As were measured. The correlation between these impurities and the film properties and the importance of monitoring their distribution are discussed in order to illustrate the applicability of the technique.