Method for programming multi-level nitride read-only memory cells
AssigneeMacronix International Co., Ltd.
InventorsHsiang-Lan Lung, Chao-I Wu
Life of this patent
Estimating the term…
Abstract
A method of programming data regions in a nitride read-only memory cell is described. In an erased state, the nitride read-only memory cell exhibits a low Vt value. A data region that is to be programmed to a highest Vt value is programmed first. Remaining data regions in the nitride read-only memory cell are programmed in a time order according to their descending Vt values. For a nitride read-only memory cell that, in an erased state, exhibits a high Vt value, a data region that is to be programmed to a lowest Vt value is programmed first with remaining data regions programmed in a time order according to their ascending Vt values.
Claims30
A method, comprising:
- providing a memory cell having plurality of data regions, each data region being programmable to one of a plurality of program values;
- obtaining a plurality of program verify (PV) levels for the plurality of the data regions according to the plurality of program values, thereby defining a collection of PV level and data region associations;
- creating a ranking of a plurality of associations of the collection according to the PV levels of the plurality of associations;
- and
- programming at least one of the data regions according to the ranking.
Dependencies are inferred from the claim text.