Charge injection in metal-ZnO-SiO2-Si structures

Abstract

The charge injection phenomenon occurring in metal‐ZnO‐SiO₂‐Si (MZOS) structures is quantitatively analyzed yielding a detailed model of the injection process. Theoretical capacitance‐voltage and charge‐voltage relationships describing the operational behavior of the gated MZOS‐C structure are first established to provide a firm foundation for the interpretation of experimental data. Key experimental results, arranged so as to retrace the logical sequence of conclusions leading to the adopted charge injection model, are next described and discussed. In negatively biased illumination‐relaxed structures all of the injected charge is shown to be located in deep‐level interfacial traps and a dipole‐like layer or surface barrier is found to exist in the near vicinity of the ZnO‐SiO₂ interface. Finally, a discussion is presented detailing both the stationary and transient aspects of the charge injection model formulated in accordance with experimental observations.