Read disturb in flash memories: reliability case

It is known that program/erase cycling of Flash memories induces a degradation of the tunnel oxide insulating property usually referred to as Stress-Induced Leakage Current (SILC). An issue related to SILC is the read disturb, affecting cells in an addressed word-line, which can cause electron injection through tunnel oxide in the floating gate of erased cells during read operation. Read disturb can also be present in Flash memory with a weak tunnel oxide quality: aim of this paper is to discuss in detail the effect of this read disturb phenomena. Cell Failure Density (CDF) extrapolation from experimental data using statistical method is able to estimate defect probability and application’s failure rate for both SILC and weak tunnel oxide quality cases.