: Nanoscale Surface Modification by the Focused Ion Beam @ University of Virginia

The Ga+ focused ion beam (FIB) is a highly versatile method for nanoscale control of surface structure and chemistry, allowing us to locally modify the surface according to surface topography, surface chemistry, surface strain fields, surface crystallinity, and surface reactivity. We have used this approach to demonstrate exquisite control of Ge nucleation on FIB-patterned Si(100), Figure 1. These experiments have been performed in a unique UHV transmission electron microscope (TEM) in collaboration with Frances Ross??? group at IBM Yorktown Heights, which is equipped with digermane and disilane growth sources, such that Ge(Si) epitaxial growth may be performed during TEM imaging. Further, using MRSEC funding, we have equipped this system with an integrated Ga+ FIB column, such that FIB surface modification, Ge(Si) deposition, and TEM imaging may all be performed within the same inter-connected UHV system. We have shown that Ga+ doses as low as 1014 cm-2 at write speeds of 100 ms/feature, enable nanoscale control of Ge QD nucleation .