Effect of Germanium content and strain on the formation of extended defects in ion implanted Silicon/Germanium

Pier-Francesco Fazzini (1) , Fuccio Cristiano (2) , Etienne Talbot (3) , Gérard Benassayag (4) , S. Paul (5) , Wilfried Lerch , A. Pakfar (6) , J.M. Hartmann (7)

1 LPCNO - Laboratoire de physique et chimie des nano-objets
2 LAAS-MPN - Équipe Matériaux et Procédés pour la Nanoélectronique
3 GPM - Groupe de physique des matériaux
4 CEMES - Centre d'élaboration de matériaux et d'études structurales
5 Child Study Center
6 ST-CROLLES - STMicroelectronics [Crolles]
7 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

We studied the evolution of extended defects in relaxed and strained Si and SiGe structures after an amorphising implant. The investigated structures included three relaxed SiGe alloy layers with various Ge contents (20, 35 and 50 at.%), a 40 nm-thick tensely strained Si layer and a 40 nm-thick compressively strained Si0.8Ge0.2 layer. Concerning the compositional effects, we found that the increase of Ge concentration in relaxed SiGe structures leads to: (i) an overall decrease of the defect stability and to (ii) an enhanced {311}-to-loops transformation. As for the strain effects, it is found that: (i) Tensile strain (in Si) retards the transformation of {311} defects into loops; (ii) compressive strain (in SiGe) enhances the transformation of {311}s into loops; (iii) in all cases, the overall defect stability is not strongly modified in the presence of strain. The observed results are discussed in terms of the various mechanisms involved, including the increase of the interstitial diffusivity in relaxed SiGe alloys (with respect to Si) and the strain effects on both interstitial equilibrium concentration and defect formation energy.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Pier-Francesco Fazzini, Fuccio Cristiano, Etienne Talbot, Gérard Benassayag, S. Paul, et al.. Effect of Germanium content and strain on the formation of extended defects in ion implanted Silicon/Germanium. Thin Solid Films, 2010, 518 (9), pp.2338 - 2341. ⟨10.1016/j.tsf.2009.09.172⟩. ⟨hal-01633467⟩