AVS 45th International Symposium
    Applied Surface Science Division Tuesday Sessions
       Session AS-TuM

Paper AS-TuM4
Auger Depth Profiling at Extreme Low Ion Energy

Tuesday, November 3, 1998, 9:20 am, Room 307

Session: Sample Preparation and Tricks of the Trade
Presenter: M. Menyhard, Research Institute for Technical Physics and Materials Science, Hungary
Authors: M. Menyhard, Research Institute for Technical Physics and Materials Science, Hungary
A. Barna, Research Institute for Technical Physics and Materials Science, Hungary
A. Sulyok, Research Institute for Technical Physics and Materials Science, Hungary
Correspondent: Click to Email
To obtain good depth resolution the sputtering induced surface roughening as well as the ion mixing should be reduced. It is well known that applying Zalar rotation with grazing angle of incidence the surface roughness is considerably reduced and the depth resolution is mainly determined by ion mixing. We have shown previously that the ion mixing proportional to the square root of the ion energy, in the energy range of 4-0.25 keV, thus the best depth resolution can be obtained by applying the lowest possible ion energy. To improve further the depth resolution we have constructed a new ion gun operating down to 0.1 keV. We will report on the experimental findings using this extreme low ion energy for depth profiling, and a novel evaluation procedure (based on dynamic TRIM simulation considering the experimentally determined roughness values ) of the depth profiles. We will show that the sputtering induced surface roughness (specimen is rotated during sputtering) depends on the ion energy; e.g. in case of GaAs we have found 1 nm and non roughness for 1 keV and 0.25 keV ion energy, respectively [1]. We will also show that the square root of ion energy dependence is also valid for this 0.25 - 0.1 keV ion energy range. We will demonstrate the capability of the method on several examples. E.g. we will show that using extreme low ion energy and our novel evaluation method for the depth profiling of a GMR structure, consisting of 1 nm thick Co/Cu layer, the demixing of Cu and Co can be demonstrated. This work was supported by grant OTKA 15880. 1. A. Barna, B. Pécz and M. Menyhard, Ultramicroscopy 70 (1998) 161-171