Reduced electron transmission in Au/GaAs diodes damaged by focused ion beam implantation studied by ballistic electron emission microscopy
Abstract
We have used ballistic electron emission microscopy to study the technologically important area of metal contacts to III-V semiconductors. Our samples are Au/GaAs diodes selectively damaged by focused ion beam (FIB) implantation. Implanted regions display reduced interface transmission as the implantation dose is increased above 5×1012 ions/cm2 for Au+ at 30 keV energy. Localized current-voltage measurements indicate that implanted regions have Schottky barrier heights slightly different from those of unimplanted regions. However, these differences are insufficient to account for the attenuated interface transmission. We invoke increased scattering from FIB-induced defects to explain the data. Defect sites in the Au or at the interface may scatter electrons away from the Schottky barrier, or increase inelastic scattering, both of which would lower interface transmission. The effects of several FIB related mechanisms on barrier heights and scattering are explored.
- Publication:
-
Journal of Vacuum Science Technology B: Microelectronics and Nanometer Structures
- Pub Date:
- November 1994
- DOI:
- 10.1116/1.587646
- Bibcode:
- 1994JVSTB..12.3712M