Switchable resistive memory with opposite polarity write pulses
AssigneeSanDisk 3D LLC
InventorRoy E Scheuerlein
Life of this patent
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Abstract
A rewriteable nonvolatile memory includes a thin film transistor and a switchable resistor memory element in series. The switchable resistor element decreases resistance when subjected to a set voltage magnitude applied in a first direction, and increases resistance when subjected to a reset voltage magnitude applied in a second direction opposite the first. The memory cell is formed in an array, such as a monolithic three dimensional memory array in which multiple memory levels are formed above a single substrate. The thin film transistor and a switchable resistor memory element are electrically disposed between a data line and a reference line which are parallel. A select line extending perpendicular to the data line and the reference line controls the transistor.
Claims31
A nonvolatile memory cell comprising:
- a switchable resistor memory element;
- and
- a thin film transistor having a channel region,
- wherein both a reference line and a data line are disposed below the channel region of the thin film transistor,
- wherein the switchable resistor memory element is disposed in series with the thin film transistor,
- wherein the switchable resistor memory element decreases resistance when a set voltage magnitude is applied across the switchable resistor memory element, and
- wherein the switchable resistor memory element increases resistance when a reset voltage magnitude is applied across the switchable resistor memory element, and wherein the polarity of the set voltage magnitude is opposite the polarity of the reset voltage magnitude.
A nonvolatile memory cell comprising:
- a switchable resistor memory element,
- a thin film transistor having a channel region, a source region, a drain region and a gate electrode,
- a select line,
- a data line disposed below the channel region, and a reference line disposed below the channel region,
- wherein:
- the gate electrode of the thin film transistor is electrically connected to or comprises a portion of the select line,
- one of the source region or the drain region of the thin film transistor is electrically connected to the data line,
- the switchable resistor memory element is electrically connected to the reference line and to the other one of the source region or the drain region of the thin film transistor,
- the select line extends perpendicular to the data line and to the reference line,
- the data line extends parallel to the reference line,
- the switchable resistor memory element is disposed in series with the thin film transistor,
- the switchable resistor memory element decreases resistance when a set voltage magnitude is applied across the switchable resistor memory element, and
- the switchable resistor memory element increases resistance when a reset voltage magnitude is applied across the switchable resistor memory element, and wherein the polarity of the set voltage magnitude is opposite the polarity of the reset voltage magnitude.
Dependencies are inferred from the claim text.