Hydrogen desorption kinetics from Si(113) surfaces were investigated using D2 temperature programmed desorption (TPD). For this purpose, clean Si(113)3 × 2 wafers were exposed to atomic deuterium at 200°C for times sufficient to provide D coverages θD ranging up to saturation, θD,sat. Corresponding low-energy electron diffraction patterns transform from 3 × 2 to 3 × 1-D to 1 × 1 with increasing θD. TPD spectra from Si(113) surfaces with θD = θD,sat consist of a first-order desorption feature (β1) centered at 515°C and a second-order desorption peak (β2) at 405°C. β2 is assigned to D2 desorption, with an activation energy of 2.16 eV, from a dideuteride surface phase while β1 is due to desorption from monodeuteride. The β1 peak consists of two components: β1,t which arises due to first order, as a result of π-bond induced ordering, D2 desorption from tetramers and β1,ad which is due to second-order D2 desorption from adatoms and second-layer surface atoms. Both β1 components have activation energies of 2.58 eV. Following monodeuteride desorption, the clean Si(113) surface again exhibits a 3 × 2 reconstruction. The TPD results are explained based upon previously proposed models for the Si(113)3 × 2 reconstructed surface.
Bibliographical noteFunding Information:
The authors acknowledge the financial support of the Materials Science Division of the US Department of Energy (DOE) under Award DEFG02-ER9645439. We also appreciate the use of the Center for Microanalysis of Materials at the University of Illinois, which is supported by the DOE.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry