Abstract

Electro-optic sampling has been used extensively for the charaterization of picosecond electronic devices such as photodetectors, transistors, and diodes [1,2]. For the large part, these studies have been with discrete devices coupled to specialized electro-optic modulators in a hybrid electrode geometry. However, there is great interest in being able to probe internal points on integrated circuits. Recently, a specialized embodiment of electro-optic sampling [3] was developed to exploit the electro-optic properties of GaAs and perform sampling directly in the substrate of GaAs integrated circuits. Any internal point of the circuit could be accessed and individual devices could be monitored in their working environment. However, GaAs is the only commonly used electronic material that is also electro-optic. The substrate technique also requires that both surfaces of the integrated circuit be optically polished and that the sampling laser beam has a photon energy below the band gap of the substrate material. One would ideally like a non-perturbative means of probing with high temporal and spatial resolution that is generally applicable to circuits fabricated on any type of substrate.

© 1987 Optical Society of America