Micron Technology, Inc.
Data Programming Techniques to Store Multiple Bits of Data Per Memory Cell with High Reliability

Abstract:

A memory system to generate data with a relation among data groups for reliably storing a predetermined number of bits per memory cell in memory cells. For example, from first groups of date bits, a second group of data bits is generated. Data groups of the predetermined number is formed to have the first groups and the second group and a predetermined relation (e.g., XOR or XNOR) among the data groups. Threshold levels of memory cells in a memory cell group are determined based on a predetermined mapping, where a threshold level of each memory cell is determined to represent one bit from each of the data groups. In the predetermined mapping, bit values represented by any two successive threshold levels differ by one bit. Threshold voltages in the memory cell group are programmed according to the threshold levels to store the data groups with improved reliability.