The reliability of electronic components is one of the major obstacle to the use of highly scaled technologies in radiative environment. The interaction of particules with semiconductor components typically generates parasitic charges. In insulators, these charges get trapped and deeply disturb the electric behaviour of the components. These trapping effects increase the sensitivity to single-event effects in memory cells, or to the propagation of parasitic signals along chains of gates in logical circuits. Hardening techniques have then to be used to overcome the sensitivity of the devices, and they come with significant penalties in terms of surface, power, or operating frequency. Microdose effects have been evidenced recently in power devices, but they seem to impact all components with ultra thin insulators.

The proposed thesis fits within a global study to model the effects of radiation on advanced microelectronic devices. The aim is to determine the parameters responsible for the effect of proton and neutron irradiation on the sensitivity of components as a function of device integration. The student will analyze experimental data from the literature and will show the effects of particle energy and angle of incidence on the response of electronic devices.

The Thesis will last for three years, with three main steps :



1) Bibliography and first calculations (6 months)

An analysis of the bibliography will be made on recent experimental results describing the microdose effect, and the increased sensitivity to proton and neutron irradiations. Then a study of the particle ? matter interaction will be performed in the specific context of protons and neutrons impacting on materials used for advanced microelectronic technologies.



2) Irradiation experiments on components

During mostly two years, the student will prepare and perform experiments on different irradiation facilities. Measurements will be made on elementary transistors or memories from 50-70 nm to 0.25 µm technologies. In particular, improvements of existing measurement techniques will need to be proposed, if needed in collaboration with other research laboratories.



3) Numerical simulations

In parallel with experiments, the student will work to analyze and model the obtained experimental results. Simulations of the response of electronic devices will be performed, and existing models will be improved. The goal of these analyses is to define the limits of existing test methods, and to propose predictive test techniques for the use of future generations of electronic devices in radiative environment.