Capacitance and $S$-Parameter Techniques for Dielectric Characterization With Application to High-$k$ PMNT Thin-Film Layers

This paper presents a method for measuring the complex permittivity of a dielectric material on a dielectric/metal stack without etching the dielectric layer. A series of circular capacitor test structures were designed and fabricated. For the first time, the unwanted capacitance
Cp
, which is formed by the oxide layer between the bottom metal layer and the silicon substrate, was defined and systematically investigated. The technique is shown to be suitable for characterization of a lead magnesium niobate-lead titanate (PMNT) material on the complex cross sections involved in the development of a novel high-
k
material. An extremely high-
k
of 1115 (high capacitance density of 26 fF/μm
²
) for a PMNT metal-insulator-metal (MIM) capacitor was achieved. In addition, low leakage current density of 2 × 10
^-10
A/cm
²
and low loss tangent were also obtained. These results clearly showed that the PMNT MIM capacitors are very promising for both decoupling and more general RF and mixed-signal applications until the year 2020, according to the International Technology Roadmap for Semiconductors (ITRS).