High-temperature charge loss mechanism in a floating-gate EPROM with an oxide-nitride-oxide (ONO) interpoly stacked dielectric

The intrinsic charge loss rate of a floating-gate EPROM cell at temperatures above 300 degrees C appears to be much higher than the prediction from the authors' previous model (1990) developed at lower temperatures. A detailed study of intrinsic charge loss rate at temperatures ranging from 340 to 430 degrees C reveals that it follows a Frenkel-Poole model with a barrier height of 1.9 eV. The physical origin of this high-temperature charge loss is proposed. The model suggests that electrons leak through the thin bottom poly oxide and nitride, and then thermally surmount the barrier at the nitride/top-oxide interface.>