Investigation of information loss mechanisms in EPROMs

The paper reports the results of accelerated life tests on p-and n-chanenl EPROMs, and compares the indication thus obtained with data from the field.The results of our experiments demonstrate that, even in recent production, contaminant diffusion significantly affects device reliability. The presence of this mechanism invalidates any effort to draw reliability information from lognormal plots of the cumulative distribution of the times to failure of all the bits in a device or in a set of devices: only the times to first bit failure for the devices of a batch should be considered. Furthermore, charge loss and contaminant diffusion seem to be uncorrelated processes.From the point of view of reliability it seems reasonable to conclude that, in spite of their increased complexity, 16 K n-channel EPROMs promise to be more reliable than 2 K devices, thanks probably to the improved technology.