Enhanced electric field modulation in the wafer-bonded InGaAs/Si APD by the groove rings in the multiplication layer

Abstract The avalanche photodiode (APD) is experiencing rapid technological advancements and expanding applications. Effective electric field engineering in APDs is critical for enhancing performance. Traditional methods for the modulation of the electric field using the charge layer often cause the carrier accumulation and non-uniform electric field distribution, limiting the performance of the APD. In this work, groove rings are introduced in the multiplication layer to efficiently modulate the electric field in the InGaAs/Si APD. This modulation is similar to that produced by the charge layer but is more effective than traditional methods. The electric field in the absorption layer can be decreased by groove rings to decrease the dark current and increase the 3-dB bandwidth. The electric field in the multiplication layer can be increased by the groove rings, leading to the better avalanche multiplication and the improvement of the gain. Additionally, the avalanche voltage is reduced by groove rings, refining the electric field distribution at the bonded interface. Importantly, groove rings enable more efficient carrier transport by avoiding carrier accumulation associated with the doping concentration of the charge layer. These findings provide theoretical guidance to achieve a higher gain-bandwidth product (GBP) of the InGaAs/Si APD.