Award

The overall objective of this program is to improve the metrology of buried dopant structures for ultraprecise devices created using Scanning Tunnelling Microscope (STM) based lithography. During fabrication, it is necessary to determine the location of existing structures so as to align new dopant structures to them precisely. This metrology therefore needs to be done in-situ during fabrication with the same probe as used for lithography Second, for quantum devices, it is proving more important that there be the desired number of dopants in a patch, rather than that their position is atomically precise. In-situ metrology allows the possibility of error correction. This is a hallmark of Atomic Precision Advanced Manufacturing. The dopant deposition and incorporation is performed in a different chamber than the lithography. Therefore, after incorporation, we need methods to reliably and efficiently relocate the general area of the nm-scale dopant structures on a mm-size sample, determine the exact location of the dopants, and to provide as far as possible quantitative information about the dopant number and location. Thus far, in the initial Phase I program, we have used a closed-loop coarse motion system and patterned substrates to return efficiently to the same position on a sample. We have developed novel high-frequency STM-based spectroscopic methods to measure dI/dV and I- V spectra at high speed during scanning, and have successfully used these methods to create bipolar dopant structures by locating B dopant regions, and then aligning P dopant patterns to them. In Phase II, we will continue to develop these novel spectroscopic imaging methods. We will pursue two tracks: metrology of dopant patch location to support Atomically Precise device fabrication for the DOE objective of UltraPrecise Manufacturing, including our parallel STTR on fabrication of bipolar devices, DE-SC0020817; and single-pixel-scale experiments to determine the sensitivity of the novel spectroscopic methods to the number of dopants in small patches to support the fabrication of quantum devices. These metrology capabilities will be incorporated into our ultraprecise lithography tool, ZyVector, enhancing its commercial value, and improve the yield and throughput of manufactured ultraprecise dopant-based devices.