Method and device for enhancing persistence of EEPROM

Abstract

The invention relates to a method and a device for enhancing persistence of EEPROM. The method comprises the step of: controlling the electric field strength of a gate oxide layer to be within the range from 10 to 15MV / cm by using a controllable high-voltage signal during the erasing or writing for an EEPROM with a floating gate tunnel oxide structure. The device comprises a clock generating drive circuit and a charge pump, wherein the clock generating drive circuit is used for generating a clock drive signal; the charge pump is used for generating a controllable high voltage signal according to the clock drive signal; and the controllable high voltage signal is used for controlling the electric field strength of the gate oxide layer to be within the range from 10 to 15MV / cm during the erasing or writing of the EEPROM with the floating gate tunnel oxide structure. By controlling the electric field strength on the gate oxide layer to be within a reasonable range, the device for enhancing the persistence of the EEPROM reduces the peak value so as to effectively enhance the persistence; and the writing and erasing time can also be shortened by using different controllable high voltage signal rising velocities.

Description

technical field [0001] The invention relates to the field of memory circuit design, more specifically, to a method and device for enhancing EEPROM persistence. Background technique [0002] Electrically Erasable Programmable Read-Only Memory (EEPROM) usually adopts a floating gate tunneling oxide (FLOTOX, floating gate tunneling oxide) structure, such as figure 1 shown. The FLOTOX structure uses the electron flow generated by the F-N (Fowler-Nordheim) tunnel effect to erase and write data on the floating gate. Under the action of the voltage difference, the barrier width between the silicon and the oxide layer becomes thinner, allowing electrons to pass through the barrier layer and cross between the conduction band of the silicon and the conduction band of the oxide layer, realizing electron injection and erasing of the floating gate . The processes of electron injection and erasure are as follows figure 2 a and figure 2 As shown in b. Among them, the relationship b...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method that can control the electric field strength on the gate oxide layer within a reasonable range, reduce its peak value, and further enhance the durability of EEPROM. persistent method

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