Measurement of real-time digital signals in a silicon bipolar junction transistor using a noninvasive optical probe

Improvement of signal to noise ratio in electro optical probing technique by wavelets filtering

“…Intensity varies with temperature change [8], charge density [4] or electric field [9]. The analyze of the properties of the reflected laser beam can be traced back to its origin, in order to obtain information on the physical parameter studied.…”

Time-resolved optical characterization of electrical activity in integrated circuits

“…Since the depletion layer of the junction is generally a small fraction of the thickness of the sample, the actual measured change in the reflected and transmitted light is even smaller. Heinrich et al [6], [7] showed that such small changes in the free-carrier concentration in the base of a bipolar transistor during switching could be detected in reflection with 1.3-m light using a very precise, phase-sensitive optical detection technique. The electric-field-induced changes in the relative phase of the probe beam enabled him to derive the voltage being applied across the base.…”

“…The first is a passive approach based on the measurement of the weak luminescence generated by hot carriers in CMOS FETs [4], [5]. The second is an active approach based on the modulation of the reflection of a probe laser beam by changes in the voltages at interfaces in Si [6]- [8]. We do not discuss test and debug techniques, which involve the implementation of test methodologies on a chip through self-test modules [9], software or tester-based approaches to fault localization, or deliberately invasive optical techniques, which use light to perturb a circuit and observe the light-induced changes in its electrical behavior.…”

A comprehensive study of the application of the EOP techniques on bipolar devices

“…These analog waveforms are inside analog devices often built in bipolar technologies. However, the origins of EOP signals from bipolar transistors junctions used in analog devices are not well known and not that much described in the literature [2].…”