Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.13: Poster

Monday, March 23, 2009, 14:30–17:00, P2

Effects of doping on the elastic properties of silicon — •Nicole Santen and Reiner Vianden — Helmholtz - Institut für Strahlen- und Kernphysik, Universität Bonn, Germany

The application of strained silicon in transistor design has led to significant progress in increasing the performance of devices. However, although the method is state of the art, many aspects in conjunction with the mechanical behaviour of strained Si layers have not yet been fully understood or even studied.

The influence of doping on the elastic properties of silicon is studied by means of the perturbed angular correlation method (PAC) using the acceptor ¹¹¹In as probe. This nuclear technique is well suited for studying strain on an atomic scale. After doping via ion implantation and subsequent annealing the Si samples are bent along the ⟨110⟩ crystal axis which leads to a uniaxial tensile strain.

It was found that the response of the silicon lattice to mechanical stress showed strong differences depending on the dopant species. Doping with acceptors does not change the elastic properties of silicon, whereas in n-doped silicon a significant strain relaxation is observed.