Abstract: New non-volatile memory devices fabricated from graded or stepped energy band gap insulator MIM or MIS structures are described. With the graded or stepped insulator, electrons or holes can be injected from the gate electrode at low to moderate applied fields. The carriers flow under the applied field into a wide energy band gap insulator having a prescribed charge trapping layer. This layer captures and stores electrons (write operation) or holes (erase operation) with 100% efficiency.

Abstract: A high field capacitor structure includes an insulating layer having a carrier trapping region between two electrodes. The trapping region improves electric breakdown characteristics of the capacitor structure and is particularly useful in avoiding the low breakdown voltages and high leakage currents normally encountered in structures with asperities, such as SiO.sub.2 over poly Si. The trapping region can be formed by chemical vapor deposition (CVD) process, by evaporation or by ion implantation. The trapping region is close to the Si, but far enough away to eliminate the possibility of reverse tunneling from discharging the traps in the absence of an applied voltage.

Abstract: A graded oxide MIM or MIS structure employs band gap grading of the insulator oxide so that holes or electrons (depending on voltage bias) can be injected into the insulator oxide under moderate electric field conditions from the contact at one interface. Electron or hole injection from the opposite interface is blocked due to the larger insulator band gap near this interface. A graded oxide metal-silicon dioxide-silicon (MGOS) semiconductor structure may be fabricated by forming several pyrolytic or CVD SiO.sub.2 layers over a relatively thick thermal SiO.sub.2 layer, with the pyrolytic SiO.sub.2 layers having sequentially increasing excess Si content. This structure may also be fabricated by controlled Si ion implantation in the thermal SiO.sub.2 layer.

Abstract: New non-volatile memory devices fabricated from graded or stepped energy band gap insulator MIM or MIS structures are described. With the graded or stepped insulator, electrons or holes can be injected from the gate electrode at low to moderate applied fields. The carriers flow under the applied field into a wide energy band gap insulator having a prescribed charge trapping layer. This layer captures and stores electrons (write operation) or holes (erase operation) with 100% efficiency.