An unexpected factor in testing for CMOS opens: the die surface

Abstract

We present the experimental evidence, for the first time, that the die surface can act as an RC interconnect, becoming an important factor in determining the voltage of a floating wire created by a CMOS open. We present a circuit model for this effect verified with HSPICE simulations. A detailed analysis of potential mechanisms behind this phenomenon is provided. We also present our measurement results for the trapped charge deposited on floating gates during fabrication.