Erratic bits in Flash memories under Fowler-Nordheim programming

Since erratic bits have been observed only after erasing in conventional Flash programmed via CHE injection, their nature was related to physical phenomena occurring during erasing [1, 3]. On the other hand, the impulse towards low power Flash applications focuses a new attention over the Fowler-Nordheim (FN) tunneling mechanism for prograrnming and it is important to fully exploit the performances of the standard Flash cell in such conditions. The purpose of this work is to show the existence of erratic bits (hereafter denoted as PE) also after FN programming in standard cells, where electrons are injected into the floating gate from the channel. This result has a relevant impact on the study of the physical nature of erratic bits, since some possible causes can now be ruled out. A full set of statistics about the PE generation and a comparison with erratic bits during erasing (denoted as EE) will be presented.