The classical Poole-Frenkel (PF) effect is the thermal emission of charge carriers from Coulombic attractive traps in the bulk of dielectrics and semiconductors, enhanced by an electric field. This mechanism results in higher than ideal currents in electronic materials, including leakage currents in conventional dielectrics, Si3N4 and SiO2; leakage in high dielectric constant materials such as Ta2O5 and BaSrTiO3, which hold great promise as gate dielectrics in DRAMs and MOSFETs; and enhanced current in Silicon Carbide (SiC) diodes. The research objective is to investigate advanced models of the PF effect and experimental techniques to characterize PF conduction in electronic devices and materials. Our primary goals are: (i) Investigate a PF model using the Fermi-Dirac function to describe the trap population statistics, while still incorporating the Boltzmann approximation for the free electron density. Model the current at voltages above saturation. (ii) Investigate this model as a function of temperature. Determine if it predicts convergence of I-V(T) curves at saturation, as our earlier research suggests. (iii) Investigate the implications of this model on our technique for measuring saturation and trap ionization potential. (iv) Fabricate MIS structures with Ta2O5, measure I-V(T) curves looking for saturation, and verify our general technique. (v) Use the Fermi-Dirac function to describe both trap and free electron population statistics for the first time. (vi) Incorporate the model in a commercial simulator, and simulate 6H-SiC p-n diodes. This research will enhance our understanding of the PF effect, and improve the accuracy of modeling this effect in electronic devices.
