Temperature effect on reflected laser probing signal of multiple elementary substructures

Abstract

Electro-Optical Probing (EOP) has shown its efficiency in the world of failure analysis. The different external physical parameters effects, especially the temperature, on the EOP signals are not well known and not that much described in the literature. In addition to thermoreflectance, the temperature is a parameter that affects directly the free carrier's distribution and carrier mobilities inside the semiconductor. Temperature also modifies the absorption coefficient and not only the refractive index as known in the thermo-reflectance domain. All the physical and environmental parameters contribute to the modulation of the reflected laser probing beam onto structures under test. In this paper we will expose the origins of the reflected laser beam and the impact of the temperature on the EOP signal. For the first time, all the parameters, including temperature, have been taken into account. It opens the door of laser probing techniques improvements in failure analysis of submicron devices.