Electrical characterization of defects introduced in p-Si1−xGex during electron-beam deposition of Sc Schottky barrier diodes

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.