The goal of this resource is to demonstrate how to reproduce key results of the paper Role of surface orientation on atomic layer deposited Al2O3/GaAs interface structure and Fermi level pinning: A density functional theory study by Hegde, Klimeck and Strachan, Applied Physics Letters, 88, 093508 (2011) using the nanoMATERIALS SeqQuest DFT simulation tool on nanoHUB. In addition to reproducing the paper's results, users can run variations of the simulation to explore the physics and conduct their own research.
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The paper in a nutshell
We investigate the initial surface reaction pathways in the atomic layer deposition (ALD) of Al2O3 on GaAs (111)A and (111)B substrates using precursors trimethylaluminum (TMA) and water to ascertain the effect of surface orientation on device performance. We find that the condition of the respective substrates prior to deposition of TMA and water has a major impact on the surface reactions that follow and on the resulting interface structure. The simulations explain the atomistic mechanism of the interfacial self-cleaning effect in ALD that preferentially removes As oxides. The electronic structure of the resulting atomic configurations indicates states throughout the bandgap for the (111)B structure. By contrast, the (111)A structure has no states in the mid-gap region, thus explaining the significant experimental difference in Fermi Level Pinning behavior for corresponding devices.
Simulation Tool: nanoMATERIALS SeqQuest DFT
Role of surface orientation on atomic layer deposited Al2O3/GaAs interface structure and Fermi level pinning: A density functional theory study Hegde, Ganesh and Klimeck, Gerhard and Strachan, Alejandro, Applied Physics Letters, 99, 093508 (2011), DOI: 10.1063/1.3624897
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