The amount of damage that radiation causes in electronic materials may be at least 10 times greater than previously thought.

That is the surprising result of a new characterization method that uses a combination of lasers and acoustic waves to provide scientists with a capability tantamount to X-ray vision: It allows them to peer through solid materials to pinpoint the size and location of defects buried deep inside with unprecedented precision.

The research, which was conducted by post-doctoral fellow Andrew Steigerwald under the supervision of Professor of Physics Norman Tolk, was published in the Journal of Applied Physics.

Norman Tolk, left, and Andrew Steigerwald in the Tolk lab. (Joe Howell/Vanderbilt)

“The ability to accurately measure the defects in electronic materials becomes increasingly important as the size of microelectronic devices continues to shrink,” Tolk explained. “When an individual transistor contains millions of atoms, it can absorb quite a bit of damage before it fails. But when a transistor contains a few thousand atoms, a single defect can cause it to stop working.”

Previous methods used to study damage in electronic materials have been limited to looking at defects and deformations in the atomic lattice. The new method is the first that is capable of detecting disruption in the positions of the electrons that are attached to the atoms. This is particularly important because it is the behavior of the electrons that determine a material’s electrical and optical properties.