AVS 45th International Symposium
    Applied Surface Science Division Thursday Sessions
       Session AS-ThA

Paper AS-ThA1
Sputtering Rate Change and Surface Roughening in SIMS Measurements Using Oblique and Normal Incidence Oxygen Bombardment, With and Without Oxygen Flooding

Thursday, November 5, 1998, 2:00 pm, Room 307

Session: SIMS - Depth Profiling and Molecular Surface Analysis
Presenter: C.W. Magee, Evans East
Authors: C.W. Magee, Evans East
S.P. Smith, Charles Evans and Associates
G.R. Mount, Charles Evans and Associates
H.-J. Gossmann, Bell Laboratories, Lucent Technologies
B. Herner, Bell Laboratories, Lucent Technologies
Correspondent: Click to Email
Measuring depth profiles for ultra-low energy ion implants in Si requires accurate analyses within the top 1 to 10 nanometers of the sample surface where the "surface transient" affects secondary ion yields. Flooding the Si surface with oxygen during analysis is an accepted method for reducing the magnitude of the surface transient effect. However, a recent study by Wittmaack and Corcoran@footnote 1@ suggests that flooding with oxygen when using 2 keV oblique incidence O2 bombardment will result in an unavoidable change in the sputtering rate for the first 20-40 nanometers of the depth profile. Another recent study, this one by Jiang and Alkemade@footnote 2@, substantiated the claims of Wittmaack and Corcoran. Jiang and Alkemade used 1keV O2 bombardment instead of 2 keV, and they found that the depth of sputter rate change extended less than 11.7 nanometers. The study of Jiang and Alkemade used a Si sample in which contained internal Ge delta layers which were grown by MBE at intervals of 11.9 nanometers. This sample allowed them to compare unambiguously the apparent depth of the Ge layers to the known depths, thus exposing any changes in sputtering rate throughout the structure of 10 equally spaced Ge delta layers. The weakness of the Jiang and Alkemade experiment lay in the rather wide spacing of the delta layers (11.9 nanometers) as well as the fact that different energies and angles of primary ion incidence were not tried. This present study is an extension of the Jiang and Alkemade work. It involves using a similar MBE sample with internal marker layers to also determine, unambiguously, enhancements in initial sputter rates and the depths to which the enhanced initial sputter rates extend. Most importantly, we have investigated a large portion of the energy-angle of incidence parameter space and have found several sets of conditions of oblique incidence with oxygen bombardment which show virtually no enhanced sputter rate at the beginning of the analysis. Data will also be shown which duplicates the sputtering conditions of the experiments shown in reference 1. We will show that some of the conclusions drawn by the authors of reference 1 are not supported by our data. @FootnoteText@ @footnote 1@K. Wittmaack and S.F. Corcoran, J.V.S.T. B 16(1), 272 (1998). @footnote 2@ Z.X. Jiang and P.F.A. Alkemade, Proc. 11th Annn. Conf. On SIMS, edited by G. Gillen, R. Lareau, J. Bennett and F. Stevie, John Wiley & Sons, (1998).