High-resolution depth profiling equipment

The concept of the design of a dedicated depth profiling equipment is based on experience gained from ion-milling experiments over more than four decades, in the preparation of thin specimens for TEM [6], 

It has been established that hillocks, terraces, pits and cones are the most common surface features generated by ion sputtering. The abundance of these features, their growth rate and the general morphological formation depend strongly on the conditions of sputtering and on the nature of the bombarded material as well [7,8]. Based on TEM experience, it can be concluded that low ion 

The sputtering gas (Xe, or He, but most frequently Ar) is introduced directly into the gun, which is enclosed apart from the ion exit aperture. The pressure in the ion gun is about two orders of magnitude higher than that in the analyzing chamber, where it is lower than 10 mbar. 

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In quadrupole-based SIMS instruments, mass separation is achieved by passing the secondary ions down a path surrounded by four rods excited with various AC and DC voltages. Different sets of AC and DC conditions are used to direct the flight path of the selected secondary ions into the detector. The primary advantage of this kind of spectrometer is the high speed at which they can switch from peak to peak and their ability to perform analysis of dielectric thin films and bulk insulators. The ability of the quadrupole to switch rapidly between mass peaks enables acquisition of depth profiles with more data points per depth, which improves depth resolution. Additionally, most quadrupole-based SIMS instruments are equipped with enhanced vacuum systems, reducing the detrimental contribution of residual atmospheric species to the mass spectrum. 

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