A new technique for measuring threshold voltage distribution in flash EEPROM devices

A new, simple test circuit for evaluating the reliability of flash EEPROM devices is described. It measures threshold voltage (V/sub th/) distributions of a large number of cell transistors with easy static operation similar to I-V curve measurement. Moreover, each cell transistor in a large array is selectable to measure static characteristics. This circuit makes it possible to measure the V/sub th/ distribution even in the negative region after erase operation for a NAND-type EEPROM.

[1]  T. Lewis,et al.  Flash EPROM disturb mechanisms , 1994, Proceedings of 1994 IEEE International Reliability Physics Symposium.

[2]  R. Kirisawa,et al.  A NAND structured cell with a new programming technology for highly reliable 5 V-only flash EEPROM , 1990, Digest of Technical Papers.1990 Symposium on VLSI Technology.

[3]  D. M. Hoffstetter,et al.  A systematic test methodology for identifying defect-related failure mechanisms in an EEPROM technology , 1994, Proceedings of 1994 IEEE International Conference on Microelectronic Test Structures.

[4]  Fujio Masuoka,et al.  Sub-Halfmicron Flash Memory Technologies (Special Section on High Speed and High Density Multi Functional LSI Memories) , 1994 .