RESUMEN
Our manuscript contained data from unconverged rigorous coupled wave approximation (RCWA) simulations that resulted in incorrect description of minima locations. Here, converged RCWA simulations are presented with corrected minima behavior described. The principle of plasmonic enhancement and its use in ellipsometric test structures is maintained.
RESUMEN
In this paper, we propose a cross-grating structure to enhance the critical dimension sensitivity of one dimensional nanometer scale metal gratings. Making use of the interaction between slight changes in refractive index and localized plasmons, we demonstrate sub-angstrom scale sensitivity in this structure. Compared to unaltered infinite metal gratings and truncated finite gratings, this cross-grating structure shows robust spectra dependent mostly on the dimension of the smaller line width and pitch. While typical scatterometry simulations show angstrom resolution at best, this structure has demonstrated picometer resolution. Due to the wide range of acceptable specifications, we expect experimental confirmation of such structures to soon follow.