Doping-spike LWIR PtSi Schottky IR detector fabricated by molecular beam epitaxy

Summary form only given. It is demonstrated that by thinning the p ⁺ layer to ~10 Å, the effective Schottky barrier heights can be reduced without the formation of a potential spike, and, consequently, the undesired tunneling process can be eliminated. Doping-spike PtSi detectors were fabricated on double-side polished Si (100) wafers with a resistivity of 30 Ω-cm. The 10-Å-thick p ⁺-Si layers were grown by molecular beam epitaxy (MBE) at 450°C using elemental boron as the dopant source with doping concentrations ranging from 5×10¹⁹ to 2×10²⁰ cm^-3. The PtSi layers were formed in situ by depositing undoped Si and Pt followed by annealing at 400°C. By varying the doping concentrations of the 1-nm-thick doping spikes from 1×10²⁰ cm^-3 to 2×10²⁰ cm ^-3, the cutoff wavelengths have been extended to 14, 18, and 22 μm, with effective optical potential barriers of 0.09, 0.069, and 0.057 eV, determined by Fowler plots, with emission coefficients comparable to those of conventional PtSi detectors with similar PtSi thicknesses