Multiphoton free-carrier injection with intense laser light: 3D-Failure assessment inside semiconductor integrated devices – MultiPhoton e-Inject

The MultiPhoton e-Inject project will conduct the first study exclusively devoted to strong laser field ionization physics in the transparency domain of semiconductors. The project aims at taking benefit of the specificities of high order multiphoton interactions to develop novel advanced optical solutions for failure assessment inside semiconductor devices.

We will address scientific questions at all time scales involved in intense laser-condensed matter interactions. We will develop a methodology based on beam depletion to have a better understanding of the non-linear ionization physics (pump depletion), carrier dynamics (ultrafast probe depletion) and subsequent material modifications (IR optical probes) in direct band-gap semiconductors (GaN, GaAs). In the experiments, we will use femtosecond infrared pulses (2 to 10 µm) that will be tightly focused inside calibrated material slabs. The study will be conducted to provide optimized control parameters (laser) to achieve interactions the most in favor of multiphoton ionization (over mechanisms like avalanche). Then, carrier injection will become extraordinary controllable and repeatable.

Under optical breakdown threshold, high-order multiphoton free-carrier injection will translate in strongly band-gap dependent absorption. The technique that will be developed to observe this process in the focal region will be used to map out materials and imperfectivities with sub-micron resolution in 3D space inside integrated devices. This new so-called Multiphoton Laser Stimulation (MLS) technique will add to the array of non-linear microscopies, providing a superior spatial resolution due to the higher nonlinear nature of the process.

Above deterministic material breakdown threshold, we will investigate modification regimes that are attractive for direct writing or local corrections of semiconductors. This has potential application in microelectronics and telecommunications.

Failure analyses become a major strategic aspect in the semiconductor industry to improve the reliability and designs of integrated devices. Looking at the future, Multiphoton Laser Stimulation will offer new routes to providing complete solution packages (from defect detection to correction) for the microelectronics industry.