Department of Theoretical Physics,
V. Lashkaryov Institute of Semiconductor Physics, 41, prospect Nauky, 03680 Kyiv, Ukraine
*E-mail: koroteev@ukr.net

Abstract. Transport theory for modeling the electric characteristics of high-quality p-n
diodes has been developed. This theory takes into account a non-uniform profile of p-
doping, finite thickness of the quasi-neutral regions and possible non-uniformity of the bulk
recombination coefficient. The theory is based on related solutions of the Poisson equation,
drift-diffusion equation and continuity equation with a generation-recombination term
taking into account the simple band-to-band generation/recombination model. We have
ascertained that the non-uniform profile of p-doping can lead to formation of p-n junctions
with a specific two-slope form of the electrostatic barrier and two regions with the high
built-in electric fields. We have found that at strong p + -doping the band structure of the
InSb p-n junction has the form that can facilitate the emergence of additional mechanisms
of current flow due to the tunneling and avalanche effects at the reverse bias. Using the
literary data of the electron and hole lifetimes in InSb at cryogenic temperatures, we have
found that the coefficient of bulk recombination can have an essential spatial dependence
and considerably increases in the space charge region of p-n diode. The theory was applied
to our analysis of p-n InSb diodes with p + -doping by using Be-ion implantation performed
in ISP NASU. The theory predicts optimal conditions for detection of infrared emission.
The technological process of fabrication, processing and testing has been described in
details. Theoretically, it has been found that for parameters of the fabricated diodes and at
77 K the dark currents limited by diffusion and generation-recombination mechanisms
should be less than 0.1 μA at the inverse bias of the order of 0.1 V. The measured diode’s
I-V characteristics were expected to have strong asymmetry, however, dark currents are by
one order larger than those predicted by theory. The latter can be associated with additional
current mechanisms, namely: tunneling and avalanche effects.