| AVS 56th International Symposium & Exhibition | |
| Applied Surface Science | Tuesday Sessions |
| Session AS-TuP |
| Session: | Applied Surface Science Poster Session |
| Presenter: | M.H. Engelhard, Pacific Northwest National Laboratory |
| Authors: | M.H. Engelhard, Pacific Northwest National Laboratory T. Droubay, Pacific Northwest National Laboratory V. Shutthanandan, Pacific Northwest National Laboratory D.R. Baer, Pacific Northwest National Laboratory S.A. Chambers, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
We report quantitative analysis of pulsed laser deposition (PLD) of LaAlO3/SrTiO3 heterostructures performed using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS). Pulsed laser deposition (PLD) has been the method of choice for the growth of LAO/STO heterostructures in many laboratories. PLD practitioners generally assume that the stoichiometry of the target is preserved in the process of vaporizing and condensing the target material onto the substrate. However, researchers do not usually conduct detailed materials characterization measurements that would ensure that this assumption is valid. We recently initiated a study of the spatial distribution of condensed La and Al on 2” diameter Si substrates held at ambient temperature during PLD of a LAO target. The substrates were fixed in position relative to the laser plume and did not rotate during growth. We found that there is considerable spatial variation in composition of La and Al deposited on the Si from a single crystal LAO target, even at laser fluences well above the ablation threshold. The on-axis geometry, in which the axis of the laser plume intersects a portion of the substrate, clearly leads to a significant enrichment of La and an Al deficiency. Although the variations are apparent in both XPS and RBS, we have further quantified the composition in XPS by comparison with standards and sensitivity factors specifically determined for our instrument. A La to Al ratio of 1:1 is achieved only over a narrow range of off-axis plume angles. XPS and RBS determination of the composition as a function of position on the substrate will be reported. We present a comparison of XPS LAO quantifications with and without overlayer correction from surface adventitious hydrocarbon contamination using the La 4d line with a relatively high kinetic (KE) energy of 1,383 eV with a lower KE La 3d5/2 line at 651 eV.