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.

Gold and chromium Schottky barrier diodes (SBDs) were deposited on epitaxially grown n-GaAs layers in a sputter system at different sputtering conditions. The SBD properties were determined by current-voltage (I-V) and capacitance-voltage (C-V) measurements, while deep level transient spectroscopy (DLTS) was employed to study the sputter deposition-induced defects. The results showed that the sputter deposition process induced surface and sub-surface disorder which introduces electrically active defect levels in the GaAs bandgap. Even though the rectification characteristics of the SBDs on n-GaAs are degraded by these defects, it appeared that the sputter system could be optimized to provide higher quality SBDs. For the first time we report a metastable defect introduced in epitaxial n-GaAs during sputter deposition.