Stroboscopic scanning electron microscopy.

High frequency cyclic voltages on a specimen surface have been studied pictorially, in the scanning electron microscope, by applying the principle of the sampling oscilloscope. The electron beam in the microscope column is pulsed, and the phase varied with respect to that of the waveform on the specimen. With 10 ns electron probe pulse length, a microcircuit voltage distribution, which is varying at 7 MHz, may apparently be stopped in time by this method of stroboscopy. Hence, a stationary picture may be obtained at any chosen phase within the cycle.