Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Oxides and Insulator Surfaces II
O 89.12: Talk
Thursday, March 10, 2016, 18:00–18:15, H4
ALD growth of Al2O3 on Stepped Surface of HOPG and Ag-HOPG — •Zied Rouissi1, Karsten Henkel1, Massimo Tallarida2, and Dieter Schmeißer1 — 1Brandenburg University of Technology Cottbus-Senftenberg — 2ALBA Synchrotron, 08290 Cerdanyola del Vallès, Barcelona, Spain
Atomic Layer Deposition (ALD) is an excellent deposition technique to grow thin film with high homogeneity coverage on ideal surfaces. Here we are interested in the growth properties on non-ideal (stepped, inert) surfaces. Using STM we studied the growth of Al2O3 by ALD on stepped surface of HOPG and silver covered HOPG (Ag-HOPG). The HOPG sample was cleaved to and then cleaned by N2 in vacuum. We obtain regular steps with terrace widths of 50nm * 500nm. Ag was deposited by thermal deposition on the HOPG. The Al2O3 growth at RT was studies after the first, third, and fifth cycle. Silver evaporation leads to step decoration with island of 1nm-7nm. On the terraces we find the formation of 2D domain of Ag chains. The features caused by the individual ALD cycles of Al2O3 depend on the terrace widths of the HOPG substrate. For small terraces (*100nm) we obtain a growth of 2D domains ( 20nm-25nm) on the edge steps and in the middle of the terrace. For large terraces (*100nm) we find agglomeration of the precursors on individual nucleation sites. Here 3D islands are formed with a height of up to 5nm in the fifth ALD cycle.