This paper presents a fast method for descrambling verification of a flash array using an IR laser. The basic effect of how the flash cell reacts to the irradiation is studied first; and then, it is shown how to take advantage of this reversible effect to quickly verify the descrambling of the flash array of a modern microcontroller. The goal of this study is to find a way to deliberately affect the programming state of a specific flash memory cell, so the altered state can be read out by standard test equipment and be correlated to the physical position of the cell. Information on the mechanism of Fowler Nordheim tunneling, ONO-tunneling, hot electrons, and laser-induced hot electron injection is provided. The application for fast descrambling of a NVM array is shown.

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