Quantitative analysis of thin aluminium-oxynitride films by EPMA

Thin films of aluminium oxynitride with diverse composition were prepared b y dc-magnetron sputtering of aluminium, utilising sputtering power as well as argon, oxygen and nitrogen gas flows to vary the composition. Since film properties depend mainly on the content of incorporated oxygen and nitroge n, a method for quantitative analysis of the main constituents based on ele ctron probe micro analysis with energy dispersive detection was developed. The excellent precision of the quantitative results for aluminium as well a s oxygen and nitrogen are shown. Further more, a film layer analysis progra m was applied for the quantification of several films deposited under the s ame deposition parameters on silicon wafers, from 520 nm dawn to 40 nm thic kness, showing that electron probe micro analysis with energy dispersive de tection is a reliable method for quantitative compositional analysis of thi n aluminium oxynitride films down to approximately 20 nm thickness. Since t his method of analysis provides only bulk information, expected inhomogenei ties of the depth distribution of the film components were checked by secon dary ion mass spectrometry depth profiles of two thin films and correlated to the EPMA results. The thickness of the films was determined by ellipsome try.