Analysis of detrap current due to oxide traps to improve flash memory retention

Author

Yamada, Ren-ichi ; Mori, Yuki ; Okuyama, Yutaka ; Yugami, Jiro ; Nishimoto, Toshiaki ; Kume, Hitoshi

Author_Institution

Central Res. Lab., Hitachi Ltd., Tokyo, Japan

fYear

2000

fDate

2000

Firstpage

200

Lastpage

204

Abstract

To improve flash memory retention characteristics, we study detrap current due to oxide traps in metal-oxide-semiconductor structures (MOS capacitors and MOSFETs). We show that threshold voltage shift due to detrap current in flash memories can reach 0.6 V for 1 year. This value is detrimental for flash memory retention. Next, we analyze the two types of conduction mechanism of the detrap current, which are direct tunneling to the anode from deeper traps and thermally excited electron tunneling to the oxide conduction band from shallower traps. The deeper traps are generated by electron injection during Fowler-Nordheim stressing, while the shallower traps are generated by hole injection

Keywords

MOS capacitors; MOSFET; electron traps; flash memories; hole traps; integrated circuit reliability; interface states; tunnelling; 1 year; Fowler-Nordheim stressing; MOS capacitors; MOSFET; Si-SiO₂; conduction mechanism; constant current stress; constant voltage stress; deep traps; detrap current; direct tunneling; electron injection; flash memory retention characteristics; hole injection; metal-oxide-semiconductor structures; oxide conduction band; oxide traps; shallow traps; thermally excited electron tunneling; threshold voltage shift; Charge carrier processes; Electron emission; Electron traps; Flash memory; MOS capacitors; MOSFET circuits; Pulse measurements; Stress; Threshold voltage; Tunneling;

fLanguage

English

Publisher

ieee

Conference_Titel

Reliability Physics Symposium, 2000. Proceedings. 38th Annual 2000 IEEE International

Conference_Location

San Jose, CA

Print_ISBN

0-7803-5860-0

Type

conf

DOI

10.1109/RELPHY.2000.843915

Filename

843915