Highly sensitive PtSi/porous Si Schottky detectors

Presents the first experimental results on PtSi/porous Si Schottky detectors. Si pores have been filled by Pt through electrodeposition. Under proper temperature treatment, Pt reacts with Si creating a PtSi layer that uniformly covers the walls of the pores. The excess unreacted Pt inside the pores is etched away leaving empty spaces behind. The spectral response of such a detector is very wide, covering from 0.9 up to at least 7 μm of IR radiation in back illumination mode. Excellent responsivities, such as 60 A/W at 1 μm and 0.96 A/W at 4 μm of IR radiation is exhibited. Reverse bias current-voltage characteristics exhibit a breakdown type behavior with a breakdown voltage at about 10 V. The general shape of the reverse bias I-V curve, the wide spectral range, and high responsivity are explained through tunneling and avalanche multiplication. It is proposed that large fringing fields developed at sharp edges of the porous surface cause tunneling and avalanche multiplication.