Picosecond photoemission probing of integrated circuits: Capabilities, limitations, and applications

The capabilities and limitations of the novel photoemission probing technique for signal measurements on internal nodes of VLSI integrated circuits are reviewed with respect to the range of possible applications of this method. Aspects such as voltage sensitivity, time resolution, minimum accessible feature size, sensitivity to perturbation effects, and impact on the circuit under test are considered. It is concluded that the especially high voltage sensitivity of this new method opens the field of diagnostics of circuits with ultrafast devices but partly low signal repetition rates, which is not accessible by other means. Such chips include, for example, complex logic chips and special telecommunication chips.