Watching semiconductor circuitry work

Semiconductor devices that are not generally thought of as light sources do emit radiation in the visible and the near infrared as they operate. Observation of this electroluminescence furnishes insight into the operation of the devices and of the circuitry that they constitute but it requires an extremely sensitive light detector and picosecond time resolution. This can be achieved using a Mepsicron™ photodetector system that enables single photon counting time-correlated imaging with a spatial resolution of about 1 μm and a time resolution approaching 10 ps. Information extracted from the time-resolved imagery can be compared with circuit layout and topology and individual device structures and with electrical measurements that are performed concurrently. These time-correlated measurements allow signal waveforms to be determined optically, much as the waveforms measured electronically with an oscilloscope and microprobing, but with the advantage that the acquisition is entirely non-invasive. Images can be dissected in both space and time to provide information for individual components of a circuit or regions of a device. This imaging equipment has been used in our laboratory for measurements on Si, GaAsP and GaN technologies and analyses will be presented