Contactless Testing by Commercial E-Beam Instruments JFET
Original Publication Date: 1980-Oct-01
Included in the Prior Art Database: 2005-Feb-14
A scanning Auger microprobe (SAM) or, alternatively, a scanning electron microscope (SEM) equipped with energy analysis provides a simple way to do contactless testing of voltages at test points on a chip. If a sample is biased at -V with respect to the electron energy analyzer, the spectrum of kinetic energies E* of electrons is like that shown by the solid curve in the figure. Many of the electrons are true secondaries, which produce a peak just above E* = V. If the sample is biased at - (V+V(o)), the entire spectrum is shifted toward higher kinetic energies (to the right) by V(o), changing the electron current in the region near E*(test) = V + (V(o)/2/) drastically.