Mapping of mechanical stress in silicon thin films on silicon cantilevers by Raman microspectroscopy

摘要

We have used plasma enhanced chemical vapor deposition (PECVD) to deposit silicon thin films (similar to 0.2-1 mu m) with different crystallinity fractions on Nanosensors PtIr5 coated atomic force microscopy (AFM) cantilevers (450 x 50 x 2 mu m(3)). Microscopic measurements of Raman scattering were used to map both internal stress and extrinsic stress induced in the films by bending the cantilevers using a nanomanipulator (Kleindiek Nanotechnik MM3A). Thanks to the excellent elasticity of the cantilevers, the films could be bent to curvature radii down to 300 gm. We observed the stress induced shift of the TO-LO phonon Raman band of more than 3 cm(-1) for fully microcrystalline film corresponding to the stress similar to 0.8 GPa. The shift of the similar film with amorphous structure was similar to 2.5 cm(-1).