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Investigation of hard-oxide-layers by XFS
Abstracts
Auger peaks to the contribution of primary, secondary and inelastically scattered Auger electrons. One of the major problems in quantitative Auger analysis is the removal of this background to obtain an accurate measurement of the peak intensity. This problem is traditionally overcome by recording differentiated spectra, but the information specifically contained in the background is then lost. We will first discuss a simple theoretical treatment to assess the respective contribution of primary electrons, secondary electrons and inelastic Auger electrons. The interest of using the background to normalise the data as well as to get information on the in-depth concentration will also be pointed out. Finally, it will be shown that combination of spect r a - i n s t e a d of measurement peak intensity--might be an alternative for quantitative Auger analysis.
perature and at 77 K. The emphasized role of the YBaCuO compounds and their metastability is well recognisable from the trends of electronic-density of states against the concentration of the components.
Investigation of hard-oxide-layers by XFS J Kojnok, Z Dankhfizi and A Szfisz, Ertrvos University, Budapest,
Hungary and K Fiuck and Gy Szalai, Hungarian Optical Work, Budapest,
Hungary Oxidation of liquid aluminum E B Bag and A Stucki*, Yu-59203 Rogoznica, Yugoslavia and
*h~stitut Applied Physics, ETH-Ziirich, Brown Boverie & Cie AG, Forschungszentrum, CH 5405 Baden-Diittvil, Switzerland This paper describes the experiments accomplished at the ETHZtirich in the aim to advance the understanding of the initial oxidation of liquid aluminum. The experimental arrangement, a special Auger spectrometer with the hybrid electron-ion gun and the system for manipulation of liquid aluminum, will be described in detail. All Auger and electron energy loss measurements are made at a residual gas pressure of less than 5.3 x 10-to mbar. For oxidation pure 02 is introduced at constant pressure of 6.6 x 10 - 6 mbar and the oxidation is followed up to a dose of 36 000 Langmuir. After 36 000 L exposure the sample is solidified and a concentration depth profile measured. To achieve an oxygen free starting liquid aluminum surface it was necessary to use extreme clean starting aluminum sample; the 4N purity aluminum was not sufficient. Using single crystals grown from zone melted aluminum as starting material made it possible to achieve an oxygen free surface within the sensitivity limit of Auger spectrometer for oxygen. Also the fact that the surface plasmon peak was higher than the volume plasmon peak was an indication for very clean surface. Exposing such a clean surface to oxygen up to I000 L dose showed growth neither of the oxygen Auger peak nor oxidised AI L23V°V° peak at 53 eV. Then a rapid rise of both peaks follows with a pronounced knee at 3000 L followed by much slower growth of both peaks up to the end exposure of 36 000 L. These investigations will be discussed in more details and some comparison made with the experiments of oxidation of solid aluminum at high temperatures.
The SXS investigation of YBaCuO ceramics J Kojnok, Z Dankh/tzi, I Jfinosi, A Szfisz, Ertovrs University,
Budapest, Hungary A soft X-ray investigation of the perovskite-type high Tc superconductors is presented on the ReBa2CuxOy (Re= Y, Eu: 1.5 ~< x ~< 9 : 6.3 ~
A systematic investigation of the vacuum-deposited hard-oxidelayers has been made by the complex analysis of the relevant technological and measurable spectroscopical parameters. The soft X-ray spectroscopies with electron and fluorescent excitations, special mass- and optical-density measurements were used for identification of chemical, mechanical and optical properties of the given samples. The relation between the chemicalshort-range order, the density and the sample preparation is discussed. The considerable modification of the well-known Clausius-Mosotti rule have been observed depending on the oxygen concentration in the sample.
Metal surface topography generated by Q-switched Nd : YAG laser S Lugomer, M Stipan~i~ and M Kerenovi~, Electrotechnical
Faculty, Banja Luka, Yugoslavia A comparative study of laser-metal surface interaction was performed. Roughly polished surface of 1 mm thick metal plates of Ta, W and Mo were irradiafed by the KORAD Q-switched Nd : YAG laser (2 = 1.06 #m), under the same conditions : operating mode TEMOO, repetition rate varied from 5 to 15 kHz, pulse duration from 120 to 300 ns depending on the repetititon rate, the output power was constant (3W) in all conditions. For the same choice of the operating parameters, a quite different behaviour was observed in the following effects: (i) the surface roughening; (ii) the crack initiation; (iii) the crack orientation with respect to the scan direction; (iv) the crack size; (v) the cracking-net generation; (vi) the partial melting localized in the crack vicinity ; (vii) the crater formation. The surface analysis was performed by SEM on Leitz, type 2000 electron microscope. Special attention was paid to the small cracks running perpendicular to the laser scan direction, and whose size of ~ 1 pm is comparable with the laser wavelength. They were found only in the case of W, while for Ta and Mo only the cracking-nets (different in size) were observed. This seems to be an indication of different mechanisms behind the cracking phenomena initiated by laser irradiation in these groups of metals. As a unique feature in all the cases (for a particular choice of operating parameters), a surface melting localized on the crack's edge appears, accompanied by the limited material flow, resulting in irregular and complicated topography.
229
Auger peaks to the contribution of primary, secondary and inelastically scattered Auger electrons. One of the major problems in quantitative Auger analysis is the removal of this background to obtain an accurate measurement of the peak intensity. This problem is traditionally overcome by recording differentiated spectra, but the information specifically contained in the background is then lost. We will first discuss a simple theoretical treatment to assess the respective contribution of primary electrons, secondary electrons and inelastic Auger electrons. The interest of using the background to normalise the data as well as to get information on the in-depth concentration will also be pointed out. Finally, it will be shown that combination of spect r a - i n s t e a d of measurement peak intensity--might be an alternative for quantitative Auger analysis.
perature and at 77 K. The emphasized role of the YBaCuO compounds and their metastability is well recognisable from the trends of electronic-density of states against the concentration of the components.
Investigation of hard-oxide-layers by XFS J Kojnok, Z Dankhfizi and A Szfisz, Ertrvos University, Budapest,
Hungary and K Fiuck and Gy Szalai, Hungarian Optical Work, Budapest,
Hungary Oxidation of liquid aluminum E B Bag and A Stucki*, Yu-59203 Rogoznica, Yugoslavia and
*h~stitut Applied Physics, ETH-Ziirich, Brown Boverie & Cie AG, Forschungszentrum, CH 5405 Baden-Diittvil, Switzerland This paper describes the experiments accomplished at the ETHZtirich in the aim to advance the understanding of the initial oxidation of liquid aluminum. The experimental arrangement, a special Auger spectrometer with the hybrid electron-ion gun and the system for manipulation of liquid aluminum, will be described in detail. All Auger and electron energy loss measurements are made at a residual gas pressure of less than 5.3 x 10-to mbar. For oxidation pure 02 is introduced at constant pressure of 6.6 x 10 - 6 mbar and the oxidation is followed up to a dose of 36 000 Langmuir. After 36 000 L exposure the sample is solidified and a concentration depth profile measured. To achieve an oxygen free starting liquid aluminum surface it was necessary to use extreme clean starting aluminum sample; the 4N purity aluminum was not sufficient. Using single crystals grown from zone melted aluminum as starting material made it possible to achieve an oxygen free surface within the sensitivity limit of Auger spectrometer for oxygen. Also the fact that the surface plasmon peak was higher than the volume plasmon peak was an indication for very clean surface. Exposing such a clean surface to oxygen up to I000 L dose showed growth neither of the oxygen Auger peak nor oxidised AI L23V°V° peak at 53 eV. Then a rapid rise of both peaks follows with a pronounced knee at 3000 L followed by much slower growth of both peaks up to the end exposure of 36 000 L. These investigations will be discussed in more details and some comparison made with the experiments of oxidation of solid aluminum at high temperatures.
The SXS investigation of YBaCuO ceramics J Kojnok, Z Dankh/tzi, I Jfinosi, A Szfisz, Ertovrs University,
Budapest, Hungary A soft X-ray investigation of the perovskite-type high Tc superconductors is presented on the ReBa2CuxOy (Re= Y, Eu: 1.5 ~< x ~< 9 : 6.3 ~
A systematic investigation of the vacuum-deposited hard-oxidelayers has been made by the complex analysis of the relevant technological and measurable spectroscopical parameters. The soft X-ray spectroscopies with electron and fluorescent excitations, special mass- and optical-density measurements were used for identification of chemical, mechanical and optical properties of the given samples. The relation between the chemicalshort-range order, the density and the sample preparation is discussed. The considerable modification of the well-known Clausius-Mosotti rule have been observed depending on the oxygen concentration in the sample.
Metal surface topography generated by Q-switched Nd : YAG laser S Lugomer, M Stipan~i~ and M Kerenovi~, Electrotechnical
Faculty, Banja Luka, Yugoslavia A comparative study of laser-metal surface interaction was performed. Roughly polished surface of 1 mm thick metal plates of Ta, W and Mo were irradiafed by the KORAD Q-switched Nd : YAG laser (2 = 1.06 #m), under the same conditions : operating mode TEMOO, repetition rate varied from 5 to 15 kHz, pulse duration from 120 to 300 ns depending on the repetititon rate, the output power was constant (3W) in all conditions. For the same choice of the operating parameters, a quite different behaviour was observed in the following effects: (i) the surface roughening; (ii) the crack initiation; (iii) the crack orientation with respect to the scan direction; (iv) the crack size; (v) the cracking-net generation; (vi) the partial melting localized in the crack vicinity ; (vii) the crater formation. The surface analysis was performed by SEM on Leitz, type 2000 electron microscope. Special attention was paid to the small cracks running perpendicular to the laser scan direction, and whose size of ~ 1 pm is comparable with the laser wavelength. They were found only in the case of W, while for Ta and Mo only the cracking-nets (different in size) were observed. This seems to be an indication of different mechanisms behind the cracking phenomena initiated by laser irradiation in these groups of metals. As a unique feature in all the cases (for a particular choice of operating parameters), a surface melting localized on the crack's edge appears, accompanied by the limited material flow, resulting in irregular and complicated topography.
229