US Patent 7583530 Multi-bit memory technology (MMT) and cells

Non-volatile multi-bit memory cells are programmed by hot electron programming and erased by high voltage tunneling, or by the use of a lower voltage Metal-Insulator-Metal (MIM) Diode carrier generation method and technology called the Tunnel-Gun (TG), in which the use of a Nitride layer or a silicon-nodule layer having location-specific charge storage elements with no spreading allows easy implementation of multi-bit technology. If charges are stored in the traps in the Nitride storage layer, an Oxide Nitride Oxide is used as the storage element. If charges are stored in layer of discrete silicon-nodules separated by a thin insulating film, an Oxide silicon-nodule Oxide storage element is used as the storage layer.