Silicide/Si/sub 1-x/Ge/sub x/ Schottky-barrier long-wavelength infrared detectors

In this paper, we demonstrate for the first time both Pd/sub 2/Si/Si/sub 1-x/Ge/sub x/ and PtSi/Si/sub 1-x/Ge/sub x/ Schottky-barrier long-wavelength infrared detectors. By employing a thin silicon sacrificial cap layer for silicide formation, Ge segregation effects and consequent Fermi level pinning when metal directly reacts with Si/sub 1-x/Ge/sub x/ alloy are eliminated. The Schottky barrier height of the silicide/Si/sub 1-x/Ge/sub x/ detector measured by internal photoemission decreases with increasing Ge fraction, allowing tuning of its cutoff wavelength. The cut-off wavelength has been extended beyond 8 mu m in PtSi/Si/sub 0.85/Ge/sub 0.15/ detectors. It has been shown that high quantum efficiency and ideally low leakage can be obtained from these detectors. The fabrication processes are easily integrable with the current PtSi/Si focal-plane-array technology.<>