Neighboring word line program disturb countermeasure for charge-trapping memory

摘要

Techniques for reading data from memory cells arranged along a common charge trapping layer. One example is in a 3D stacked non-volatile memory device. Memory cells on a word line layer WLLn can be disturbed by programming of memory cells on an adjacent word line layer WLLn+1, resulting in uncorrectable errors. The memory cells on WLLn are read in a data recovery read operation which applies an elevated pass voltage to WLLn+1. The elevated pass voltage decreases and narrows the threshold voltages on WLLn, which facilitates reading. The data recovery read operation compensates for the lower threshold voltages of the cells by lowering the control gate voltage, raising the source voltage or adjusting a sensing period, demarcation level or pre-charge level in sensing circuitry. The elevated pass voltage can be stepped up in repeated read attempts until there are no uncorrectable errors or a limit is reached.