Responsivity Comparison of Different Photodiode Structures

Silicon-based photodiodes with different topologies are designed and simulated using the Sentaurus Technology Computer-Aided Design (TCAD) tool. These topologies comprise i) a conventional device with a single n-well, ii–iii) two versions of a branched (interdigitated) structure with a regular well, iv–v) a ring-like well structure with two different contact configurations, and finally vi) a structure that has a well in the center of the device. Designed devices are simulated with incident light within various wavelengths from 0.6 μm to 0.7 μm. The effect of the reflection coefficients of anode and cathode contacts is also investigated. The ring-like structure is the most effective in producing the highest cathode current for a given input optical power. Doping type effects are inquired as well.