Stress-induced leakage current of tunnel oxide derived from flash memory read-disturb characteristics

This paper describes the characteristics of the stress-induced leakage current of tunnel oxide derived from Flash memory read-disturb characteristics, The following three items were newly observed. First, the threshold voltage shift (Delta V-th) of the memory cell under the gate bias condition(read disturb condition) consists of two regions, a decay region and a steady-state region, The decay region is due to both the initial trapping or detrapping of the carriers in the tunnel oxide and the decay of the stress-induced leakage current of the tunnel oxide, The steady-state region is determined by the saturation of the stress-induced leakage current of the tunnel oxide. Second, the read disturb life time is mainly determined by the steady-state region for the oxide thickness of 5.7-10.6 nm investigated here, Third, a high-temperature (125 degrees C) write/erase operation degrades the steady-state region characteristics in comparison with room temperature (30 degrees C) operation, Therefore, accelerated write/erase tests san be carried out at higher operation temperatures.