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

• Published in: IEEE transactions on electron devices Vol. 45; no. 2; pp. 482 - 486
• Main Authors: Satoh, S., Hemink, G., Hatakeyama, K., Aritome, S.
• Format: Journal Article
• Language: English
• Published: IEEE 01-02-1998
• Subjects: Capacitors; Degradation; Flash memory; Flash memory cells; Leakage current; Saturation magnetization; Steady-state; Stress; Temperature; Testing
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/16.658684

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 (/spl Delta/V/sub 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/spl deg/C) write/erase operation degrades the steady-state region characteristics in comparison with room temperature (30/spl deg/C) operation. Therefore, accelerated write/erase tests can be carried out at higher operation temperatures.