Internal waveform measurements of the MOS three-transistor, dynamic RAM using S.E.M. stroboscopic techniques

Stroboscopic electron beam blanking of a conventional SEM was employed to analyze high speed dynamic RAM operations. In the system described a time resolution of 20 nanoseconds was used to produce voltage contrast (V.C.) images of single events. Also the SEM was operated as a sampling oscilloscope to display timing waveforms from individual circuit nodes. Several types of 4K RAM (MCM6605) operations were analyzed to evaluate this technique in debugging MOS LSI circuits. The operations analyzed were memory cell timing waveforms, data-node storage, and node bootstrapping. The interaction of the SEM with the MCM6605 operation was also analyzed.