Interface Electric Field Confinement Effect of High-Sensitivity Lateral Ge/Si Avalanche Photodiodes

A novel lateral Ge /Si avalanche photodiode without a charge region is investigated herein using device physical simulation. High field is provided by the band-gap barrier and build-in field at the Ge /Si interface in the vertical direction. Modulating the Si mesa thickness ( 0-0.4?μ?m) and impurity concentration of the intrinsic Si substrate ( 1×1016-4×1016?cm-3) strengthens the electric field confinement in the substrate region and provides a high avalanche multiplication in the Si region. When the Si mesa thickness is 0.3?μ?m, and the impurity concentration of the Si substrate is 2×1016?cm-3, the Lateral Avalanche PhotoDiode (LAPD) exhibits a peak gain of 246 under 1.55?μ?m incident light power of -22.2?dBm, which increases with decreasing light intensity