Raman-microanalysis of strain and crystal orientation in laser-crystallized silicon

In this work we report on the use of Micro-Raman-Spectroscopy (MRS) to determine residual strain in cw-laser crystallized silicon on insulator (SOI)-thin layers and to measure slight deviations in crystal orientation which occur along the crystallization path during the crystallization process. The spatial resolution achieved is 0.8 μm. Relative peak positions of the silicon phonon line have been measured with a reproducibility better than ±0.02 cm^-1. Frequency shifts in the crystalline layer were in the range of -1.5 cm^-1. This corresponds to a tensile biaxial stress of 3.8 kbar. Polarization dependent intensity monitoring has been carried out to measure the local tilt of crystal orientation in crystallized thin layers. For this we use polished cross-cut specimens which enable a change in observation direction, thus achieving an angular resolution of ±1°. At a crystallization path length of 90 μm the measured backward tilt of the [001]-axis was 3°.