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Schottky barrier diodes (SBDs) were fabricated on epitaxially grown n-GaAs materials, with different free carrier densities, by electron beam (e-beam) evaporation of Pt at various rates. The quality of the SBDs was evaluated by standard current-voltage (I-V) measurements, while the defects introduced during e-beam evaporation were characterized by deep level transient spectroscopy (DLTS). The results showed that if the GaAs was shielded during Pt deposition from stray electrons originating at the e-beam filament, high quality SBDs were formed. However, if the GaAs was not shielded during deposition, the quality of the diodes was poor and the degree to which their characteristics deviated from the ideal case increased as the total electron dose reaching the substrate increased (for slow evaporation rates) and as the free carrier density of the GaAs increased. DLTS revealed that several surface and subsurface defects were introduced during metallization without the electron shield and it is shown that these defects are responsible for the poor device quality. The nature of some of these defects depended on the free carrier density of the GaAs.

Scandium (Sc) Schottky barrier diodes were fabricated by electron-beam (EB) deposition on epitaxially grown p-Si1−xGex strained films with x=0.0–0.2. The EB deposition was performed either with or without shielding the Si1−xGex samples. The barrier height and the defects introduced during EB deposition have been investigated as a function of Ge composition. Our results showed that the barrier height decreased as the band gap changed with increasing Ge content. The defect properties were studied with deep-level transient spectroscopy. The most prominent defect observed in p-Si was a hole trap H(0.53) at Eν+0.53 eV. Increasing the Ge content led to a decrease in the activation energy of this defect and this decrease followed the same trend as the band-gap variation, suggesting that the main defect detected in p-Si1−xGex is the same as that observed in p-Si.

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