Multi-level flash memory with temperature compensation
AssigneeSamsung Electronics Co., Ltd.
InventorsTae-Hee Cho, Yeong-Taek Lee
Life of this patent
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Abstract
A multi-level semiconductor memory device preferably includes a plurality of wordlines connected to memory cells configured to store multi-level data. A first circuit supplies a temperature-responsive voltage to a selected wordline in order to read a state of a selected memory cell. A second circuit supplies a predetermined voltage to non-selected wordlines. The first circuit preferably includes a semiconductor element that varies its resistance in accordance with temperature. Reliable program-verifying and reading functions are preferably provided despite migration of threshold voltage distribution profiles due to temperature variations.
Claims20
A semiconductor memory device comprising:
- a plurality of memory cells configured to store multi-level data;
- a plurality of wordlines connected to the plurality of memory cells;
- and
- a first circuit configured to supply a temperature-dependent voltage to a selected one of the wordlines to read or verify a state of a selected memory cell.
A semiconductor memory device comprising:
- a memory cell array comprising a plurality of memory cells, wordlines, and bitlines, said memory cells configured to store multi-level data;
- a first voltage generation circuit configured to generate a first voltage having a predetermined level;
- a second voltage generation circuit configured to generate a temperature-dependent flexible reference voltage;
- and
- a third circuit configured to compare the first voltage to the flexible reference voltage, said third circuit further configured to supply a temperature-dependent output voltage to a selected one of the wordlines, said output voltage corresponding to a difference between the first voltage and the flexible reference voltage.
A method of operating a multi-level data state semiconductor memory device having a plurality of wordlines connected to a plurality of memory cells, said method comprising:
- selecting a wordline from among a plurality of wordlines, said selected wordline corresponding to a selected memory cell;
- supplying a temperature-dependent voltage to the selected wordline;
- and
- supplying predetermined voltages to nonselected wordlines.
Dependencies are inferred from the claim text.