Comparison of FET electro-optical modulation for 1300Â nm and 1064Â nm laser sources

Detecting laser beam reflectance modulation intensity (RMI) from the back-side obtains useful information about the functional performance of an integrated circuit (IC). In this paper, we want to focus on the different signal signatures coming from different regions of a single transistor (gate and drain) to better understand the origin of these signals using two different wavelengths (1064 nm and 1300 nm). For this reason, very simple functional cases have been selected for analysis and simulation of the optical properties: varactor in inversion (gate region) and the reverse-biassed pn-junction (drain region).