8. Impedance Spectroscopy/High Temperature Dielectric Characterization

The CDS is investigating impedance spectroscopy as a potential tool to aid process and better determine reliability issues. Impedance spectroscopy is used to identify local interface phenomena in multilayer devices. Specifically, we can model the grain, grain boundary, and electrode of base-metal dielectric systems. Models deconvolute general impedance data collected from millihertz to megahertz and assigns a characteristic leaking capacitor to describe electrodes, grain boundaries, and grains. These capacitors are then compared under different process and degradation conditions to determine sources that limit lifetime performance. Changes in local resistance, capacitance, and capacitance-voltage behavior are used to determine the sources for degradation. Figure 1(a) shows typical impedance data for an X5R capacitor plotted in the complex plane. This particular dielectric models as a four-element system that includes a core and shell region for the grain, Figure 1(b). We frequently aim to correlate the macroscopic impedance data to local TEM data. A nickel-BaTiO3 interface obtained with high resolution microscopy is shown in Figure 1(c).

Figure 1(a).

Figure 1(b)	Figure 1(c).