Importance

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Abstract

A flash memory cell is of the type having a substrate of a first conductivity type having a first region of a second conductivity type at a first end, and a second region of the second conductivity type at a second end, spaced apart from the first end, with a channel region between the first end and the second end, a floating gate insulated from a first portion of the channel region and adjacent to the second region, a first control gate adjacent to the floating gate and insulated therefrom, and insulated from a second portion of the channel region, and adjacent to the first region, a second control gate capacitively coupled to the floating gate, and positioned over the floating gate. A method programming the cell to one of a plurality of MLC states comprises applying a current source to the first region. A first voltage is applied to the first control gate sufficient to turn on the second portion of the channel region. A second voltage is applied to the second region, sufficient to cause electrons to flow from the first region towards the second region. A third voltage is applied to the second control gate sufficient to cause electrons in the channel region to be injected onto the floating gate. The third voltage is applied uninterrupted until the floating gate is programmed to the one state.

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First Claim