AVS 50th International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeP

Paper AS-WeP3
An XPS Comparison of ALD and PLD Grown Thin Al@sub 2@O@sub 3@ Layers

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: J.M. Sturm, University of Twente, The Netherlands
Authors: A.I. Zinine, University of Twente, The Netherlands
J.M. Sturm, University of Twente, The Netherlands
R.G. Bankras, University of Twente, The Netherlands
H. Wormeester, University of Twente, The Netherlands
B. Poelsema, University of Twente, The Netherlands
Correspondent: Click to Email
Atomic Layer Deposition (ALD) is regarded as a suitable deposition technique for high-K metal oxides. Pulsed Laser Deposition (PLD) is an attractive alternative for a fast identification of new materials. A comparative XPS study of thin Al@sub 2@O@sub 3@ films grown by ALD (5, 10 and 20 nm) and PLD (15 and 30 nm) was made. This analysis is possible without a sputterprofile and is thus not compromised by co-sputtering. Water and trimethylaluminum were used as precursors in the ALD process. Fully oxidized alumina films with good stoichiometry and a band gap of 6.8±0.1 eV were obtained in all cases. The Si 2p XPS peak of the ALD films grown on hydrogen terminated Si with 50 ALCVD cycles did not show the formation of SiO@sub 2@. Angle resolved measurements gave a thickness of 4.2 nm, while a film grown on silicon oxide was 5.0 nm thick as expected for 50 cycles for the recipe used. This indicates growth inhibition in the first case. We note that both films showed a negligible carbon contamination. Freshly prepared ALD samples showed an O 1s XPS peak, composed of oxygen bonded to aluminium and a 1.6 eV energy shifted feature. Angle dependent measurements showed that this shifted feature is limited to the two topmost layers and can be identified as an OH species. Prolonged air exposure introduced a third component, which is attributed to oxygen bonded with carbon. The PLD samples grown in oxygen or argon ambient pressures of 0.1 mbar showed both a significant carbon content. However, only samples prepared in oxygen ambient exhibited carbide contamination and oxidized interfacial silicon.