Tsinghua Science and Technology


avalanche photodiodes, lateral structure, electric field confinement, high gain


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.


Tsinghua University Press