Mechanical stress dependence of the Fermi level pinning on an oxidized silicon surface

H. Li (1) , L. Martinelli (1) , Fabian Cadiz (1) , A. Bendounan (2) , S. Arscott (3, 4) , F. Sirotti (2, 1) , A.C.H. Rowe (1)

1 LPMC - Laboratoire de physique de la matière condensée
2 SSOLEIL - Synchrotron SOLEIL
3 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
4 NAM6 - IEMN - Nano and Microsystems - IEMN

A combination of micro-Raman spectroscopy and micro-XPS (X-ray photo-electron spectroscopy) mapping on statically deflected p-type silicon cantilevers is used to study the mechanical stress dependence of the Fermi level pinning at an oxidized silicon (001) surface. With uniaxial compressive and tensile stress applied parallel to the ⟨110⟩ crystal direction, the observations are relevant to the electronic properties of strain-silicon nano-devices with large surface-to-volume ratios such as nanowires and nanomembranes. The surface Fermi level pinning is found to be even in applied stress, a fact that may be related to the symmetry of the Pb0 silicon/oxide interface defects. For stresses up to 240 MPa, an increase in the pinning energy of 0.16 meV/MPa is observed for compressive stress, while for tensile stress it increases by 0.11 meV/MPa. Using the bulk, valence band deformation potentials the reduction in surface band bending in compression (0.09 meV/MPa) and in tension (0.13 meV/MPa) can be estimated.

Mots clés: Silicon; Mechanical stress; Interface defect; X-ray photoelectron spectroscopy; Surface Fermi level pinning; Raman spectroscopy

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Sciences de l'ingénieur [physics]

H. Li, L. Martinelli, Fabian Cadiz, A. Bendounan, S. Arscott, et al.. Mechanical stress dependence of the Fermi level pinning on an oxidized silicon surface. Applied Surface Science, 2019, 478, pp.284-289. ⟨10.1016/j.apsusc.2019.01.207⟩. ⟨hal-02319831⟩