Strain engineering—deliberately stretching or compressing a crystal lattice—is used in advanced microelectronics to accelerate electron flow. Even a fraction of a percent change in lattice spacing can produce faster, more power-efficient processors. CEA-Leti has therefore developed local quantitative material-deformation measurement and now offers a strain-mapping service built on transmission electron microscopy (TEM) with precession electron diffraction (PED). Conventional electron diffraction uses a fixed beam angle and often yields complex patterns due to dynamic scattering; PED instead rotates the beam in a conical sweep, recording a cleaner, more complete diffraction pattern over dozens of orientations.

Workflow starts with roughly 80 nm-thick lamellae prepared by focused ion beam (FIB) milling, inserted into a PED-equipped TEM. Scanning diffraction then measures crystal lattice parameters with high spatial resolution across device regions. The resulting strain maps achieve 1 nm spatial resolution and ~0.02% precision, placing CEA-Leti among the world's leaders in nanoscale metrology. The process has been simplified and accelerated for higher throughput and faster turnaround. Three TEMs are now equipped for PED, increasing sample capacity and making the service accessible to more qualified microscopists. Bernier highlights the combined fundamental research and application-driven engineering expertise that turned an experimental methodology into a practical, routine characterization service.

​​​​​​The performance of advanced microelectronic devices depends especially on the efficient transport of electrical charges. These transport properties are strongly related to deformation of the crystal lattice.

Strain engineering, which involves deliberately stretching or compressing a crystal lattice, is used to boost the speed of electron flow in a device. Even a fraction of percent change in lattice spacing can translate into faster and more power-efficient processors. That is why at CEA-Leti we have been working in recent years on the local and quantitative measurement of material deformations, which are at the heart of today’s cutting-edge devices.​​​​

CEA‑Leti's strain‑mapping service uses transmission electron microscopy (TEM) to carry out precession electron diffraction (PED). In ordinary electron diffraction the beam hits the crystal at a fixed angle, often producing complex patterns because of dynamic scattering. PED solves that by rotating the beam in a conical sweep, recording a more complete diffraction pattern over dozens of orientations. The result is higher-quality diffraction data that can be turned into strain maps.

The workflow starts with ultra‑thin lamellae—cross‑sections of a chip that are roughly 80 nm thick— prepared using focused ion beam (FIB) milling.

Once the specimen is ready, it is inserted into a TEM microscope equipped with a PED module. Scanning diffraction allows the lab to measure the lattice parameters of the crystal with high spatial resolution in different regions of a device.

The technique delivers strain maps with 1 nm spatial resolution and ~ 0.02 % precision, which places CEA-Leti among the world's leaders in nanoscale metrology.

The technique has been simplified and accelerated where possible to enable higher throughput and make better use of the instruments. The result is a faster turnaround time for characterization requests.

Three TEMs are now equipped to perform PED measurements, allowing CEA-Leti to handle a larger volume of samples and making the service accessible to more qualified microscopists.

The project didn't happen in isolation. Bernier​​ emphasizes the combined expertise of the team members that made it possible:

That partnership between fundamental research and application‑driven engineering helped turn an experimental methodology into a practical, routine characterization service. ​