VOLTAGE MEASUREMENT WITH AN ELECTRON BEAM PROBE.

In order to study the mode of operation of semiconductor devices, it may be necessary to measure voltages on the surface of the device to a high spatial resolution. The spreading resistance of a mechanical wire probe in contact with a semiconductor surface limits the resolution to approximately 5 mu m, and loading of the device by the probe may inhibit its normal operation while under test. The use of an electron beam permits high spatial resolution (probe size less than 0. 1 mu m), accurate positioning by reference to the SEM image, and negligible perturbation of the device's operation.