Multilevel ferroelectric memory cell for an integrated circuit
AssigneeNaMLab gGmbH
InventorsStefan Slesazeck, Halid Mulaosmanovic
Life of this patent
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Abstract
An integrated circuit includes a ferroelectric memory cell. The ferroelectric memory cell includes a ferroelectric layer stack comprising at least one ferroelectric material oxide layer. Each of the ferroelectric material oxide layers includes a ferroelectric material that is at least partially in a ferroelectric state. The ferroelectric layer stack comprises at least two ferroelectric domains. Further, the voltage which is to applied to the layer stack to induce polarization reversal differs for the individual domains such that polarization reversal of individual domains or of a portion of the totality of ferroelectric domains within the ferroelectric material of can be attained.
Claims19
An integrated circuit element comprising:
- a first electrode;
- a second electrode;
- and
- a storage layer disposed between the first and the second electrodes, the storage layer being partially in a ferroelectric state with two ferroelectric domains such that voltages necessary to reach coercive fields of the two ferroelectric domains differ by at least 50 mV from each other.
A method for writing an integrated circuit element comprising a storage layer disposed between first and the second electrodes, the storage layer being partially in a ferroelectric state with first and second ferroelectric domains, and a voltage source to apply a voltage to the storage layer, the method comprising:
- applying a write voltage pulse sequence to the storage layer via the voltage source, the write voltage pulse sequence including:
- applying a voltage pulse of a coercive voltage of the first ferroelectric domain changing a polarization of the first ferroelectric domain or applying a voltage pulse of a coercive voltage of the first and second ferroelectric domain changing the polarization of the first and second ferroelectric domain.
A method for sensing an integrated circuit element comprising a ferroelectric storage layer disposed between first and the second electrodes, the ferroelectric storage layer being partially in a ferroelectric state with two ferroelectric domains, and a voltage source to apply a voltage to the storage layer, the method comprising:
- applying a sensing voltage pulse sequence between the first electrode and the second electrode having a voltage value that is suitable to sense a polarity of the ferroelectric storage layer by a current measurement.
Dependencies are inferred from the claim text.