Piezo-Spectroscopic Stress Measurement near PZT-Microstructures on Silicon

摘要

Domain formation and polarization in ferroelectric films probably are strongly influenced by intrinsic stress. Raman microscopy offers the possibility to get informations about the stress state even in film structures with lateral dimensions of several ten microns. PZT (Pb[Zr,Ti]O_3) microstructures with Pt bottom electrodes sputtered on silicon wafers were investigated using the Raman peak of the single crystalline silicon. Near edges of Pt and PZT films Raman shifts |△v| ≤ 1,5 cm~(-1) were measured corresponding to stresses in the silicon substrate near the interface in the order of several hundred MPa. The Raman shift profiles are dependent on the particular geometry of the investigated structures and specific microstructure defects near the edge. An estimate of the stress in the PZT film was obtained by modelling the stress in the silicon as a function of the distance from one edge using a finite element code.