Introduction of defect levels in resistive-evaporated n-Si Schottky barrier diodes

Defect levels in n-type Si Schottky barrier diodes made by resistive evaporation have been investigated by deep level transient spectroscopy. Three defect levels are observed at 0.16, 0.14, and 0.12 eV below the conduction band. The concentrations of the defect levels exponentially decrease into the substrate. The defects are introduced during etching process rather than evaporation process. The concentration of the defects increase with the thickness of the layer removed by etching before Schottky metal deposition, and decrease with the etching rate. This suggests that the defect levels are produced near the surface and are driven into the substrate during etching processes.