Investigation of the aluminium oxidation in an oxygen plasma excited by microwaves

Al-coatings of approximately 50 nm thickness were deposited by thermal evap oration on Si(100)-wafers. The changes of the Al-films during oxygen plasma treatment in a 2.45-GHz microwave discharge at a pressure of 0.1 Pa were i nvestigated. To study the oxidation kinetics the formed aluminium oxide was investigated using grazing incidence X-ray reflectometry (GIXR), XPS and I R and the residual Al layers were studied using grazing incidence X-ray dif fractometry (GIXRD). It was observed that oxygen plasma treatment lead to r eactions at low temperatures (< 300<degrees>C) where thermal treatment show no noticeable effect. The developed oxide is X-ray amorphous. To quantify the alumina formation the change of the film thickness and of the Al(111) p eak integral intensity of the non-reacted part of aluminium were determined time-controlled. From these results it can be concluded that two processes , an oxidation and a sputtering process, influence the oxide film growth. T he crystallization behaviour was investigated by means of in situ GIXRD dur ing post-annealing in dependence on different plasma treatments. (C) 2000 E lsevier Science B.V. All rights reserved.