Kinetics and Energetics of Ge Condensation in SiGe Oxidation
Résumé
The fabrication of an ultrathin Ge-rich SiGe body on silicon on insulator (SOI) is highly challenging for the next generation of fully depleted complementary metal-oxide semiconductor devices that will be implemented in the near future. Ge-rich layers (GRLs) could be fabricated using a Ge enrichment process which takes place during dry thermal oxidation of SiGe thin films. While several studies make use of the GRL for many applications, the basic mechanism at work during the enrichment process is still unclear. In this study, we address the mechanism of formation of GRL and we determine the major driving forces of the enrichment process. We highlight the particular role played by the Si0.5Ge0.5 which is stabilized for various experimental conditions and strain levels. A systematic study demonstrates that the 50% Ge content is stabilized by a self-limited interdiffusion process regulated by the entropic term of the formation energy, which is a minimum at Si0.5Ge0.5 at the expense of the elasticity-driven interdiffusion. The process developed provides an easy and efficient way to produce planar GRLs free of dislocations with abrupt GRL/Si interfaces and tunable thickness. These GRLs could be fashioned for the heterogeneous integration of various systems on SOI.
Domaines
Chimie-Physique [physics.chem-ph]| Origine | Fichiers produits par l'(les) auteur(s) |
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