Structures and energetics of SiGeHz0,+1, Ge2Hz0,+1, and Si2Hz0,+1: A systematic theoretical study

The structural and energetic information of SixGeyHz and ions is crucial in understanding the deposition processes in producing SixGe1-x semiconductor materials. This work presents theoretical studies on the structures and energetics of the simplest SiGe-hydrides and cations, SiGeHz0,+1, as well as Ge2Hz0,+1 and Si2Hz0,+1 for comparison. The structures are obtained at DFT-B3LYP and MP2 levels with 6-31+G(2df,p) basis set, and the electronic energies at Gaussian-4 (G4) level. The G4 energies are used to calculate the relative energies, bond dissociation energies, the adiabatic ionization energies (IE(a)s) of neutral species, and the appearance energies (AEs) of cation fragments from SiGeH6, Ge2H6, and Si2H6. The relative energies and IE(a)s for Si2Hz and the total atomization energies of Si2Hz and Ge2Hz are compared and are in close agreement with previous theoretical and experimental studies, while the agreements on the AEs of Si2Hz+ from Si2H6 are less pronounced. The calculations suggest that the kinetic shift effect and potential barriers should be taken into account when using AEs for thermodynamic information of Si2H2+, Ge2H2+ and SiGeH2+. (C) 2011 Elsevier B.V. All rights reserved.