IrSi Schottky-barrier infrared detectors with wavelength response beyond 12 μm

Schottky-barrier infrared detectors with a 4-nm-thick IrSi electrode have been fabricated on p-Si substrates previously implanted with low-energy boron ions. Low-energy boron ion implantation has been used to form a shallow p+-Si layer that lowers the barrier height of IrSi-Si Schottky-barrier contacts by the image-force effect and field-assisted tunneling. IrSi infrared detectors with a cutoff wavelength beyond 12 μm have been obtained by this technique. The optical barrier height found by spectral response measurements is 0.100 eV, which corresponds to a detector cutoff wavelength of 12.4 μm.