Structures and energetics of SiGeH z0,+1, Ge 2H z0,+1, and Si 2H z0,+1: A systematic theoretical study

Abstract

The structural and energetic information of Si x Ge y H z and ions is crucial in understanding the deposition processes in producing Si x Ge 1− x semiconductor materials. This work presents theoretical studies on the structures and energetics of the simplest SiGe-hydrides and cations, SiGeH z 0,+1, as well as Ge 2H z 0,+1 and Si 2H z 0,+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 as) of neutral species, and the appearance energies (AEs) of cation fragments from SiGeH 6, Ge 2H 6, and Si 2H 6. The relative energies and IE as for Si 2H z and the total atomization energies of Si 2H z and Ge 2H z are compared and are in close agreement with previous theoretical and experimental studies, while the agreements on the AEs of Si 2H z + from Si 2H 6 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 Si 2H 2 +, Ge 2H 2 + and SiGeH 2 +.