title: Observations of Si field evaporation.
abstract: Field evaporation studies of crystalline <100> Si were performed in a three-dimensional atom-probe, which utilized a local electrode geometry. Several distinct phenomena were observed. Si field evaporation rates showed: (1) no measurable dependence on temperature below 110K, (2) an exponential dependence on evaporation rate as a function of temperature above 110K, and (3) no dependence on substrate doping (i.e., electrical conductivity) as high as 10 Omega cm in the temperature range of 40-150K. Two distinct evaporation modes were observed. The first was associated with approximately 1at% H+ in the mass spectrum. Negligible amounts of H were detected in the mass spectra of the second mode. When the pulse fraction (pf) was increased from 5% to 30%, the presence of H+ in the mass spectra, i.e. operation in the first mode, was associated with a degradation in mass resolution by as much as 80% for the 10 Omega cm Si samples. Conversely, no loss in mass resolution was detected for the approximately 0.001 Omega cm samples over the pf range studied.
authors.affiliation: Imago Scientific Instruments, Inc. 6300 Enterprise Lane Suite 100, Madison, WI 53711, USA. kthompson@imago.com
authors.forename: Keith
authors.initials: K
authors.lastname: Thompson
authors.forename: Jason
authors.initials: J
authors.lastname: Sebastian
authors.forename: Stephan
authors.initials: S
authors.lastname: Gerstl