Abstract
Gold Schottky contacts were deposited by rf and dc sputter deposition on epitaxially grown n type and p type GaAs. Current-voltage (I–V) measurements showed that for n-GaAs the barrier heights of sputter deposited contacts are lower than those of resistively deposited contacts, while for p-GaAs the opposite wasfound. Deep level transient spectroscopy (DLTS) revealed the presence of several sputter deposition introduced electron traps in the upper half of the bandgap. However, no hole traps in significant concentrations could be detected in the lower half of the bandgap. Depth profiling by DLTS indicated that whereas some defects were located very close to the interface, others were detected much deeper in the epitaxial layers. The concentration distributions of defects below the interface were found to depend on the sputter mode and sputter conditions as well as the free carrier concentration of the GaAs.
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