Electron beam induced deposition of pure, nanoscale Ge

Pure, nanoscale Ge dots were deposited on Si3 N4 substrates by decomposing digermane (Ge2 H6) using a focused electron beam. Deposited feature diameters are larger than that of the electron beam used for deposition by an amount comparable to the secondary electron escape depth. This result suggests that axial secondary electron emission through the surface of a growing feature limits the minimum attainable feature size. In situ, electron energy-loss spectroscopy shows that the dots are pure Ge with C contents below the carbon detection limit of less than 18%. Analyzing the bright field image in the thin film, single scattering approximation yields the height of the Ge dots allowing the average Ge deposition efficiency to be estimated.