Temperature Dependence of Leakage Current in InAs Avalanche Photodiodes

Measurement and analysis of the temperature dependence of bulk and surface leakage currents in InAs avalanche photodiodes have been performed between 77 K and 290 K. At unity gain, SU-8 passivated InAs photodiodes have low dark current densities of 100 mA/cm
²
at 290 K and 150 nA/cm
²
at 77 K. An avalanche multiplication factor of 25 was measured at 13 V and 19.5 V at 290 K and 77 K, respectively. The photodiodes exhibit dynamic resistance-area products, calculated at 0.1 V of 34 Ω-cm
²
at 290 K and 910 MΩ-cm
²
at 77 K. Our analysis showed that between the temperatures of 200 K and 290 K, the bulk leakage current is proportional to
n
_i
²
whereas the surface leakage current is proportional to
n
_i
from 77 K to 290 K, where
n
_i
is the intrinsic carrier concentration. The activation energies deduced were 0.36 eV and 0.18 eV suggesting diffusion dominated bulk current and generation and recombination dominated surface current.