This research is concerned with fundamental device physical electronics to understand the basic limitations of solid-state microstructures which rely on quantum mechanical tunneling of carriers into deep storage traps. These traps provide the basis for non-volatile memory structures in a new multi-insulator device structure--the Metal-blocking oxide-nitride-tunneling oxide-silicon (MONOS) microstructure. This research explores the physical mechanisms through which charge injection, transport, and storage is achieved in these devices. The experimental approach focuses on "scaled" microstructures to understand the fundamental mechanisms which determine the erase/write, retention, and endurance properties of these devices. An objective of this research is to develop an analytical model of the MONOS operation in terms of the nature and distribution of traps within the nitride storage layer. The research also seeks to explore the origin and control of these traps through a model of the process technology for multi-insulator film preparation. The results of this research impact the design of high density, non-volatile, silicon microstructures for high-speed, long retention, memories with greatly improved endurance to cycling.