A Novel Threshold Voltage Distribution Measuring Technique for Flash EEPROM Devices

Toshihiko HIMENO  Naohiro MATSUKAWA  Hiroaki HAZAMA  Koji SAKUI  Masamitsu OSHIKIRI  Kazunori MASUDA  Kazushige KANDA  Yasuo ITOH  Jin-ichi  MIYAMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.2   pp.145-151
Publication Date: 1996/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microelectronic Test Structures)
Category: Device and Circuit Characterization
flash memory,  Vth distribution,  reliability,  NAND flash,  nonvolatile memory,  

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A new, simple test circuit for measuring the threshold voltage distribution of flash EEPROM cell transistors is described. This circuit makes it possible to perform a reliability test for a large number of memory cell transistors with easy static operation because it reduces the measuring time drastically. In addition, this circuit can measure the highest and lowest thresh-old voltages of memory cell transistors easily. This method is suitable for performing the reliability test, such as program/erase endurance test and data retention test, for a large number of flash memory cell transistors. The usefulness of this new test circuit has been confirmed by applying it to 64 Kbit NAND-type flash memory cell array.