A New Instrument for Quantitive Measurements of High-Ionization Thereshold Elements in Nanostructures

The objective of the project is to develop a new mass spectrometric diagnostic tool that will allow quantitative measurement on a nanometer scale of elements having a high ionization potential, such as hydrogen, carbon, nitrogen, oxygen fluorine, and phosphorous. The proposed work would extend the proven capabilities of laser resonance postionization of sputtered material to enable efficient measurements of high-ionization threshold elements in nanoscale devices. Two advances are required to enable these highly sensitive and selective measurements over tens of nm scales, with essentially no matrix effects: 1) demonstrating effective one-photon resonance ionization for the chosen elements, and 2) removing vibrations and drift from existing instrumentation. Work in Phase I is aimed at developing vacuum ultraviolet laser wavelengths to accomplish the first of these requirements. Assuming successful completion of Phase I and Phase II, the high efficiency (3% to 8% useful yield) and lack of matrix effects characteristic of resonance postionization measurements would allow quantitative measurements of major constituents in extremely small dimensions (e.g., 50 nm x 550 nm x 1 nm), even in dynamic stoichiometries. Measurement of low-concentration constituents, dopants, and impurities could be performed in slightly larger volumes.