Selectively formable vertical diode circuit element
AssigneeActel Corporation
InventorsAmr M. Mohsen, Esmat Z. Hamdy, John L. McCollum
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Abstract
A programmable low impedance interconnect diode element is disclosed having a lower electrode formed of a semiconductor material of a first conductivity type covered by an insulating dielectric layer which may be in a preferred embodiment comprised of an initial layer of silicon dioxide, a second layer of silicon nitride and a third layer of silicon dioxide, covered by a layer of semiconductor material of a second conductivity type. A programmable read only memory array and a programmable logic array comprising a plurality of the above-described cells are also disclosed.
Claims9
A selectively formable vertical diode circuit element formed by a process including the steps of:
- forming a diffusion area of a first conductivity type in a semiconductor substrate of a second conductivity type,
- forming a first oxide insulating layer over said diffusion area,
- forming a second silicon nitride insulating layer over said first insulating layer,
- forming a third oxide insulating layer over said second insulating layer,
- forming a semiconductor layer of second conductivity type over said insulating layer above at least a portion of said diffusion area,
- and further a step of applying a voltage source for a controlled time between selected ones of a said diffusion areas and said semiconductor layer, at a voltage sufficient to break down said first, second, and third insulating layers and form a diode.
A plurality of selectively formable vertical diode circuit elements disposed in a semiconductor substrate of a first conductivity type, each of said elements including:
- a first electrode comprising a first region of semiconductor material of a second conductivity type disposed in said substrate,
- an insulator covering said first region, said insulator having a first layer of silicon dioxide, a second layer of silicon nitride over said first layer of silicon dioxide, and a third layer of silicon dioxide over said layer of silicon nitride, and,
- an upper layer of semiconductor material of said first conductivity type over said insulator,
- at least one of said elements further including a conductive filament in said insulator, said filament extending between and forming a PN junction between said first and second regions of semiconductor material.
A plurality of selectively formable vertical diode circuit elements disposed in a semiconductor substrate of a first conductivity type, each of said elements including:
- a first electrode comprising a first region of semiconductor material of a second conductivity type disposed in said substrate,
- an insulator covering said first region, said insulator having a first layer of silicon dioxide, a second layer of silicon nitride over said first layer of silicon dioxide, and a third layer of silicon dioxide over said layer of silicon nitride, and, an upper layer of metal over said insulator, at least one of said elements further including a conductive filament in said insulator and forming a Schottky diode contact between said metal and said first region.
Dependencies are inferred from the claim text.