Atomic scale characterization of dopants (APT)

3D nanoscale analysis of dopant in semiconductor with Atom Probe Tomography
As transistor structures continue to shrink to keep pace with Moore's Law the existing analysis and metrology techniques currently in use will no longer be sufficient to fully characterize the nanoscale devices. Atom probe has the unique capability to characterize the next-generation technology cycles by mapping the spatial distribution and chemical identity of dopants on the atomic scale.

The image on the left shows a 3D reconstruction of a patterned semiconductor test structure analysed by CAMECA's LEAP Si; a TEM picture of an equivalent structure is shown for comparison.

The polysilicon was deposited on a <100> single crystal silicon wafer, masked and etched prior to As implant.

The gate dielectric is located directly beneath the poly-Si line. The As atoms (purple spheres) are located to the side of the poly-Si line with a small amount of lateral distribution. The gate oxide and native oxide is denoted by the blue oxygen isoconcentration surface. The morphology of the oxide surface shows that the implant process resulted in considerable mixing of the native oxide and the Si substrate.

Sample compliments of Intel Corporation.
TEM image compliments of University of Florida.