Lateral Separate Absorption Multibuffer Multiplication Avalanche Photodiode Based on SOI Film

A lateral separate absorption multibuffer multiplication (LSAMBM) avalanche photodiode based on SOI film was proposed. The LSAMBM structure could nearly eliminate the edge breakdown induced by the curvature effect to improve the stability of the device, and effectively solve the conflict between the sensitive area and the junction capacitance. The step doping multibuffer could reduce the strength of the reverse electric field between absorption region and multiplication region to achieve larger strength of the electric field in the absorption region. Thus, low avalanche breakdown voltage (BV), high responsivity, and fast frequency response could be obtained simultaneously. The simulation results showed that the BV was about 8.2 V and the dark current was only 2.6 fA with a reverse bias of 4 V. When the incident light wavelength was 400 nm and optical power was equal to 0.001 W/cm 2 , the responsivity and frequency response raised to 160.05 A/W and 10 GHz with the reverse bias of 8.2 and 9.5 V, respectively. All these indicated that the LSAMBM APD could be a promising candidate for the high-speed weak-light detection.