Uwe Scheithauer

Improved sputter depth resolution in Auger thin film analysis using in situ low angle cross-sections

A none conventional approach for depth profiling of thin film systems with enhanced depth resolution has been developed using standard Auger microprobe instruments. For the preparation of an in situ low angle cross-section, the sample is partly covered by an appropriate mask. Utilising the edge of this mask, the sample is sputtered in the Auger microprobe with ions at nearly grazing incidence. In the shadow of the mask, this produces a low angle cross section through the thin film system. Then, a conventional depth profile is measured at the point of interest where part of the thin film system is covered only by a thin top layer. As demonstrated a considerable improvement of depth resolution delta z / z can be obtained by this method.

Combined AES/factor analysis and RBS investigation of a thermally treated Pt/Ti metallisation on SiO2

SummaryPt/Ti metallisation bilayers are used as bottom electrodes for ferroelectric thin films. During deposition of the ferroelectric films, these electrodes are exposed to elevated temperatures causing modifications of the Pt/Ti bottom electrode. Diffusion and oxidation of the Ti adhesion layer have been studied by the application of factor analysis to AES depth profile data and by RBS. Factor analysis was employed to extract the chemical information from the measured AES spectra and to derive semiquantitative depth profiles of the identified material compounds. RBS was used to obtain the quantitative depth distribution of the elements. By the combination of both methods, diffusion and oxidation processes were observed and could be precisely described.

Application of the analytical methods REM/EDX, AES and SNMS to a chlorine induced aluminium corrosion

SummaryScanning electron microscopy (SEM) with energy dispersive X-ray detection (EDX), Auger electron spectroscopy (AES) and sputtered neutral mass spectrometry (SNMS) have been used to characterize a chlorine induced corrosion of an aluminium metallisation. SEM/EDX detects the characteristic X-rays, that are emitted from the first few micrometers beneath the specimens surface after inner shell ionisation by the primary electrons. AES detects the alternatively ejected Auger electrons, that are generated within the topmost atomic layers of the sample. To obtain elemental concentration depth profils, the surface layers are removed by ion sputtering. Whereas AES detects the composition of the remaining surface, SNMS measures sputtered fluxes and does not suffer from preferential sputtering. As demonstrated by the example of a chlorine induced aluminium corrosion, these analytical methods are complementary with respect to quantification, chemical information and information depth. Only by simultaneous use measuring artifacts are detectable and able to be excluded from interpretation.

Long time stability of the energy scale calibration of a Quantum 2000

Abstract According to the international standard ISO 15472 the energy scale of an XPS instrument, type Physical Electronics Quantum 2000, was calibrated. It is shown, how the procedures of the ISO 15472 were adapted to the hardware and software design of the Quantum 2000. The long time stability of the energy scale calibration of the XPS instrument was investigated. The instrumented was operated with a satisfying energy scale calibration over a period of 8 years. All the time energy differences between certain peaks could be measured with the chosen precision of the energy scale calibration.

In situ low-angle cross sectioning: Bevel slope flattening due to self-alignment effects

Abstract Low-angle cross sections are produced inside an Auger microprobe using the equipped depth profile ion sputter gun. Simply the sample is partly covered by a mask. Utilizing the edge of this mask the sample is sputtered with ions. Due to the shading of the mask a cross section is produced in the sample. The slope of this cross section is considerably shallower than given by the geometrical setup. This is attributed to self-alignment effects, which are due to missing sputter cascades in the transition area between sputtered and shaded sample regions and a chamfering of the mask edge. These self-alignment effects are studied here using a 104.6xa0nm thick SiO2 layer thermally grown on a Si substrate. In this study on one hand for a fixed ion impact angle of 15.8° as function of the sputter time several in situ low-angle cross sections were produced. This way slope angles between an ultimate low slope angle of 0.014° and 0.085° were achieved. On the other hand for a fixed sputter time the ion impact angle was varied between 14.8° and 70.8°. For these samples cross section slope angles between 0.031° and 0.32° are observed. These results demonstrate the distinct slope flatting of in situ cross sectioning.