An Extended Unified Schottky-Poole-Frenkel Theory to Explain the Current-Voltage Characteristics of Capacitors Using High-k Dielectric Materials

Abstract

Historically, there is a controversy regarding the current-voltage (I-V) characteristics of thin film MIM (metal-insulator-metal) capacitors, which is quite frequently modeled by either the Schottky model or the Poole-Frenkel model. In this letter, the author points out that the two models actually can be unified. The physics underlying this model involves a non-uniform distribution of defect states such that a very large quantity of defect states exist at the two interface of the MIM capacitor while the density of defect states in the insulator bulk is relatively low, resulting in an M/n-i-n/M structure. This unified Schottky-Poole-Frenkel model can be further extended to include other effects like space charge limited current, tunneling, etc. Evidence supporting this theory will be provided.