Low Dark-Current Germanium-on-Silicon Near-Infrared Detectors

Ultralow dark current Ge/Si(100) photodiodes with low thermal budget

“…1. Their values of 4.1ϫ 10 −5 and 1 ϫ 10 −6 A / cm 2 at 1 V reverse bias are lower than those for Ge photodetectors grown previously on Si directly, 14,15,17,21 or on graded buffers 10 ͑see Table II͒. They are comparable to those of commercial bulk Ge or large-area InGaAs photodetectors.…”

Ge-on-Si photonic devices for photonic-electronic integration on a Si platform

“…Due to the reduction of threading dislocation density by the post-growth annealing, the dark leakage current is reduced to ∼20 mA/cm 2 at the reverse bias of 1 V. As summarized in Fig. 8(c), the dark leakage current tends to decrease with decreasing the threading dislocation density in Ge [23,30,31,32,33]. However, the high-temperature annealing to reduce the dislocation density could be eliminated from the viewpoint of compatibility with the CMOS process for electronic circuits, otherwise Ge layers need to be formed at the beginning of front-end process, causing a drastic change in the existing CMOS process.…”

Germanium-on-glass near-infrared detectors

“…2 shows typical dark current densities against reverse bias, with typical and minimum values of 100 and 50 mA/cm 2 , respectively, at 1 V reverse bias, i.e. among the lowest reported values in thin film Ge NIR photodiodes, 10 -20 times lower than high performance Ge-on-Si devices [7] and comparable to commercial Ge detectors. The linear scaling of the dark current with device area (see inset of Fig.…”

“…These results demonstrate the maturity of Ge on Si heteroepitaxy, although growth techniques are expensive and require conspicuous thermal budgets, often hampering their compatibility with microelectronics. In addition, even if the threading dislocations associated with the large lattice mismatch can be minimised, their residual density results in large dark current densities (typically 5 -100 mA/cm 2 ) [7]. Large dark currents must be avoided as they contribute to shot noise, which may significantly reduce the detector sensitivity.…”