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US 12,499,937 B2Granted
Flash memory device with photon assisted programming
AssigneeRambus Inc.
InventorMark D. Kellam
Life of this patent
Estimating the term…
Abstract
A flash memory cell of a flash memory device is illuminated with light during programming and/or erasing. The wavelength of the light is selected such that the photons impinging on the flash memory cell have an energy that approaches the barrier height (conduction band offset) of the tunnel insulator. Illuminating the flash memory cell during programming/erase increases the tunneling current through the tunnel insulator by way of the photon assisted tunneling (PAT) effect.
Claims17
A memory device, comprising:
- an array of flash memory cells;
- a light source to selectively direct light to illuminate the array of flash memory cells to enhance programming performance, the flash memory cells comprising a control gate, a charge holding layer, a tunnel insulator, and a substrate, the light comprising photons to strike electrons held by the charge holding layer, the photons striking the electrons held by the charge holding layer to have a photon energy that is less than the barrier height of the tunnel insulator;
- and
- control circuitry to apply a programming voltage to the control gate of at least one flash memory cell of the array of flash memory cells while the photons are striking the electrons held by the charge holding layer thereby, based on photon assisted tunneling of the electrons struck by the photons having the photon energy that is less than the barrier height of the tunnel insulator, increasing a Fowler-Nordheim tunnel current flowing between the charge holding layer and the substrate.
1 more element
A memory device, comprising:
- an array of flash memory cells, the flash memory devices of the array each having at least a first charge holding layer, a first tunnel insulator layer, a first control gate, and a first channel;
- and,
- a light source to illuminate the first charge holding layer, the light comprising photons to strike electrons held by the charge holding layer, the photons striking the electrons held by the charge holding layer to have a photon energy that is less than the barrier height of the tunnel insulator, the photons striking the electrons held by the charge holding layer thereby, based on photon assisted tunneling of the electrons struck by the photons having the photon energy that is less than the barrier height of the tunnel insulator, increasing a Fowler-Nordheim tunnel current flowing between the charge holding layer and the substrate while a programming voltage is applied to the first control gate.
A method of operating a flash memory device, comprising:
- illuminating a flash memory device array with photons, the flash memory cells of the flash memory device array comprising a control gate, a charge holding layer, a tunnel insulator, and a substrate, the photons to strike electrons held by the charge holding layer, the photons striking the electrons held by the charge holding layer to have a photon energy that is less than the barrier height of the tunnel insulator;
- concurrently with illuminating the flash memory device array, programming, using a first programming voltage, at least a first portion of the flash memory device array while the photons are striking the electrons held by the charge holding layer thereby, based on photon assisted tunneling of the electrons struck by the photons having the photon energy that is less than the barrier height of the tunnel insulator, increasing a Fowler-Nordheim tunnel current flowing between the charge holding layer and the substrate;
- and
- concurrently with illuminating the flash memory device array, programming, using a second programming voltage that has an opposite polarity to the first programming voltage, at least a second portion of the flash memory device array.
1 more element
Dependencies are inferred from the claim text.