Exploring the Capability of Multifrequency Charge Pumping in Resolving Location and Energy Levels of Traps Within Dielectric

Multifrequency charge-pumping (MFCP) experiments have been used by many groups to profile the locations and the energy levels of bulk traps within high-kappa gate dielectric stack of MOS transistors. Since the measurements involve easy generalization of the classical CP technique, the interpretation of the data has sometimes been based on uncritical generalization of classical CP theory or a simplified numerical model that does not capture the complexity and nuances of the dynamics of occupation of dielectric traps. In this paper, we develop a rigorous numerical model of MFCP technique and encapsulate/interpret the results using an intuitively simple analytical formula. Consistent with some earlier reports, we observe that MFCP experiment scans a limited region of traps within the dielectric stack. Although the degree of trap response in MFCP is a (nonintuitive) function of parameters like rise/fall time, frequency, temperature, and pulse levels, we show that only a certain combination of parameters is sufficiently orthogonal to allow unambiguous back-extraction of the trap profile.