Daniel E. Adams

Measurement of energy contrast of amplified ultrashort pulses using cross-polarized wave generation and spectral interferometry

We interfere an amplified output pulse with a copy that has been converted using third-order cross-polarized wave generation. The ASE pedestal shows as a background in the interference, yielding the short-pulse/ASE energy contrast.

Complex EUV imaging reflectometry: spatially resolved 3D composition determination and dopant profiling with a tabletop 13nm source

With increasingly 3D devices becoming the norm, there is a growing need in the semiconductor industry and in materials science for high spatial resolution, non-destructive metrology techniques capable of determining depth-dependent composition information on devices. We present a solution to this problem using ptychographic coherent diffractive imaging (CDI) implemented using a commercially available, tabletop 13 nm source. We present the design, simulations, and preliminary results from our new complex EUV imaging reflectometer, which uses coherent 13 nm light produced by tabletop high harmonic generation. This tool is capable of determining spatially-resolved composition vs. depth profiles for samples by recording ptychographic images at multiple incidence angles. By harnessing phase measurements, we can locally and nondestructively determine quantities such as device and thin film layer thicknesses, surface roughness, interface quality, and dopant concentration profiles. Using this advanced imaging reflectometer, we can quantitatively characterize materials-sciencerelevant and industry-relevant nanostructures for a wide variety of applications, spanning from defect and overlay metrology to the development and optimization of nano-enhanced thermoelectric or spintronic devices.

Prototype through-pellicle coherent imaging using a 30nm tabletop EUV source

We present preliminary through-pellicle imaging using a 30nm tabletop extreme ultraviolet (EUV) coherent diffractive imaging microscope. We show that even in a non-optimized setup, this technique enables through-pellicle imaging of a sample with no detectable impact on image fidelity or resolution.