Detailed observation of small leak current in flash memories with thin tunnel oxides

Author

Manabe, Yusuke ; Okuyama, Kousuke ; Kubota, Katsuhiko ; Nozoe, Atsushi ; Karashima, Tetsuji ; Ujiie, Kazuaki ; Kanno, Hiroyuki ; Nakashima, Moriyoshi ; Ajika, Natsuo

Author_Institution

Hitachi Ltd, Tokyo, Japan

fYear

1998

fDate

23-26 Mar 1998

Firstpage

95

Lastpage

99

Abstract

This paper describes a method for measuring the small current through the oxides on the order of 10^-20 A or less using a floating gate MOSFET and the application results on flash memories with thin tunnel oxides. The method is based on accurate measurement of the threshold voltage of a floating gate MOSFET with no charge in the floating gate. We applied the method to flash memories to investigate the leakage current behaviour through thin tunnel oxides with very small areas (<0.16 μm²), and found some anomalous phenomena which cannot be obtained from stress-induced leakage current (SILC) measurements using large capacitors. We also discuss possible mechanisms to explain the phenomena

Keywords

EPROM; MOS memory circuits; MOSFET; dielectric thin films; integrated circuit testing; leakage currents; 0.01 aA; SILC measurements; Si; SiO₂-Si; flash memories; floating gate MOSFET; floating gate charge; leak current; leakage current; thin tunnel oxides; threshold voltage; tunnel oxide area; Area measurement; Capacitors; Charge measurement; Current measurement; Flash memory; Leakage current; MOSFET circuits; Nonvolatile memory; Stress measurement; Threshold voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Microelectronic Test Structures, 1998. ICMTS 1998., Proceedings of the 1998 International Conference on

Conference_Location

Kanazawa

Print_ISBN

0-7803-4348-4

Type

conf

DOI

10.1109/ICMTS.1998.688049

Filename

688049