Analysis of the Experimental Data from MOS Structures in the Case of Large Noise-to-Signal Ratio

The signal coming from $SiO_{2}$ layer of MOS structure have large noise-to-signal ratio. This has two reasons - first: the dielectric layers have small Raman efficiency, second: the thickness of the dielectric layers are of the order of 10 nm, so the volume of the material irradiated with laser light is small. At the other side spectroscopic and optical data carry the information about important properties of the structure like mechanical stress. Distribution of mechanical stress introduce an important contribution to the electric properties of the electronic systems based on the MOS structures. Therefore, it is important to "distillate" the optical data from the noise. In this contribution the authors discuss some methods of denoising of the Raman signal. The discussed methods compare treatments like wavelet analysis or convolution. The work is illustrated with some examples of the extraction of the data coming from thin layers. The examples of application of the optical data in the description of the properties of the studied structures are presented.