Nuclear and optical analyses of MOS devices

Abstract

The characteristic dome-like shape distribution of electric parameters (with the biggest values in the middle and the lowest values in the corners of the gate) has been observed in our investigations. Taking the results of the papers into account, the following hypothesis was drawn: the shape distribution of electrical parameters has been caused by the irregular shape of stress distribution under the metal gate. To prove or deny the assumed hypothesis, a lot of investigations on stress and strain in MOS structures are being performed. The study of the atomic composition of electronic components constitutes the starting point of their characterization. Therefore, in this paper, we present experimental results of hydrogen, oxygen, aluminum, silicon, and copper concentrations in MOS structures carried out by the Rutherford backscattering spectrometry and elastic recoil detection methods. These techniques allow inter alia determination of silicon and oxygen content as a function of the position x on a wafer. On the basis of depth profile elastic recoil detection measurements performed on Al and AlSiCu gates, a much larger hydrogen content in the surface layer for MOS structure with Al gate was confirmed. Copper atoms were detected only in the AlSiCu gate.