Highly Accurate Composition Analysis of (Pb,Zr)TiO3 Using a Scanning Electron Microscope/Energy Dispersive X-Ray Spectrometer

A highly accurate composition analysis method for (Pb,Zr)TiO3 (PZT) thin films was developed that uses a scanning electron microscope/energy dispersive X-ray spectrometer (SEM/EDX). This method, highly accurate (HA)-SEM/EDX, consists of two measurements with different electron beam acceleration voltages to control the signal generation depth. The measurement time is sufficiently elongated to reduce the statistical noise. Measurement accuracy of the PZT composition is ±1%, which is sufficient to predict the electrical characteristics of PZT capacitors. We applied HA-SEM/EDX to the failure analysis of PZT capacitors, and found that composition variation was the cause of failure in both failed samples we examined. The composition variations of PZT within a Si wafer were also measured. The composition variation of a PZT film fabricated by the sol-gel method was over ±2%, which was much larger than that of PZT deposited by ozone jet evaporation method (±1%).