Surface self-diffusion of silicon during high temperature annealing

Pablo E. Acosta-Alba (1, 2) , Oleg Kononchuk (1) , Christophe Gourdel (1) , Alain Claverie (2)

1 SOITEC SA
2 CEMES - Centre d'élaboration de matériaux et d'études structurales

The atomic-scale mechanisms driving thermally activated self-diffusion on silicon surfaces are investigated by atomic force microscopy. The evolution of surface topography is quantified over a large spatial bandwidth by means of the Power Spectral Density functions. We propose a parametric model, based on the Mullins-Herring (M-H) diffusion equation, to describe the evolution of the surface topography of silicon during thermal annealing. Usually, a stochastic term is introduced into the M-H model in order to describe intrinsic random fluctuations of the system. In this work, we add two stochastic terms describing the surface thermal fluctuations and the oxidation-evaporation phenomenon. Using this extended model, surface evolution during thermal annealing in reducing atmosphere can be predicted for temperatures above the roughening transition. A very good agreement between experimental and theoretical data describing roughness evolution and self-diffusion phenomenon is obtained. The physical origin and time-evolution of these stochastic terms are discussed. Finally, using this model, we explore the limitations of the smoothening of the silicon surfaces by rapid thermal annealing. © 2014 AIP Publishing LLC.

Mots clés: Atomic force microscopy; Diffusion; Rapid thermal annealing; Silicon; Stochastic systems; Surface topography; Atomic-scale mechanisms; Diffusion equations; High-temperature annealing; Parametric modeling; Roughening transition; Roughness evolution; Thermal fluctuations; Thermally activated; Stochastic models

Domaines: Physique [physics]

Pablo E. Acosta-Alba, Oleg Kononchuk, Christophe Gourdel, Alain Claverie. Surface self-diffusion of silicon during high temperature annealing. Journal of Applied Physics, 2014, 115 (13), pp.134903 - 333. ⟨10.1063/1.4870476⟩. ⟨hal-01719499⟩