Tailorable Doping-Spike PtSi Infrared Detectors Fabricated by Si Molecular Beam Epitaxy

Abstract

By incorporating a 1-nm-thick p+ doping spike at the PtSi/Si intertace, we have successfully demonstrated extended cutoff wavelengths of PtSi Schottky infrared detectors. The extended cutoff wavelengths resulted from the reduced effective potential barriers due to the combined effects of an increased electric field near the silicide/Si intertace and the Schottky image force. The p+ doping spikes were grown by molecular beam epitaxy at 450° C using elemental boron as the dopant source, with doping concentrations ranging from 5×1019 to 2×1020 cm-3. The cutoff wavelengths were shown to increase with increasing doping concentrations of the p+ spikes. Thermionic emission dark current characteristics were observed and photoresponse in the LWIR regime was demonstrated. Furthermore, the effective potential barriers determined by the Richardson plots were used to study the electrically activated boron dopant concentrations of the thin (1-nm-thick) spikes.