Nonidealities and Dark Current in IR Photodetector Based on Silicide-Nanolayer Schottky Barrier Integrated Into a Si Microring Resonator

Using a Z-transfer model applicable to a microring resonator enhanced internal photoemission-based photodetector (MRRE-IPE-PD); we develop a model for evaluating the effect of reflections in the microring resonator (MRR) on the quantum efficiency (QE). Simulations show that a 5% increase in the reflection from an ideal case QE and MRR quality factor reduces by ~30%. We also show that further increase in the reflection can result in a dramatic decrease in QE and break the degenerate resonant frequency down into two frequencies. Considering the detuning condition in an MRR, we extend an existing model suitable for the MRRE-IPE-PD. We evaluate the effect of this nonideality on the PD QE. A detuning equal to free spectral range (FSR)/3 reduces the QE to half of its value for an ideal case. Nonetheless, for a detuning equal to FSR/2, the QE of the ideal case is retained. We also evaluate the dependence of the QE bandwidth product (QE × BW) on the MRR radius in under-critical, critical, and over-critical coupling conditions. Simulations reveal that the latter is the optimized condition, wherein the QE × BW for a PD with 2-nm PtSi decreases from 32 to 30 GHz, when the radius is increased from 7 to 10 μm.