On the origin of the dispersion of erased threshold voltages in flash EEPROM memory cells

Author

Essemi, D. ; Riccò, Bruno

Author_Institution

Dipt. di Elettronica, Inf. e Sistemistica, Bologna Univ., Italy

Volume

47

Issue

5

fYear

2000

fDate

5/1/2000 12:00:00 AM

Firstpage

1120

Lastpage

1123

Abstract

This work investigates the origin of the dispersion of tunnel-erased threshold voltages (V_T) in flash EEPROM memory cells. A clear correlation between cell-to-cell variations of tunnel current I_T and dispersion of erased V_T is demonstrated by looking at the I_T characteristics and the erasing characteristics corresponding to channel and source injection as well as at the dependence of I_T and V_T dispersion on device area and tunnel polarity. Experimental evidence is provided that nonuniform injection at poly-Si/SiO₂ interface is a major cause of erased V_T dispersion

Keywords

electric potential; flash memories; integrated memory circuits; tunnelling; Si-SiO₂; cell-to-cell variations; device area; erased threshold voltages dispersion; erasing characteristics; flash EEPROM memory cells; nonuniform injection; oxide conductivity variations; polySi/SiO₂ interface; tunnel current characteristics; tunnel polarity; tunnel-erased threshold voltages; Character generation; Conductivity; Current measurement; Dispersion; Doping; EPROM; Nonvolatile memory; Pulse measurements; Threshold voltage; Tunneling;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.841251

Filename

841251