In this communication, we report results obtained on a new InSb/InAlSb/InSb ‘bariode’, grown by MBE on (100)-
oriented InSb substrate. Because of a very weak valence band offset with InSb (~ 25meV), InAlSb is a good candidate as
a barrier layer for electrons. However, due to lattice mismatch with the InSb substrate, careful growth study of InAlSb
was made to insure high crystal quality. As a result, InSb-based nBn detector device exhibits dark current density equals
to 1x10-9A.cm-2 at 77K: two decades lower than Insb standard pin photodiode with similar cut-off wavelength.
Moreover, compared to standard pn (or pin) InSb-based photodetectors fabricated by implanted planar process or by
molecular beam epitaxy (MBE), we demonstrate that the reachable working temperature, around 120 K, of the InSbbased
nBn detector is respectively higher than 40 K and 20 K than the previous. Such result demonstrates the potentiality
of Insb detectors with nBn architecture to reach the high operating temperature.
InSb pin photodiodes and nBn photodetectors were fabricated by Molecular Beam epitaxy (MBE) on InSb
(100) n-type substrate and characterized. MBE Growth conditions were carefully studied to obtain high
quality InSb layers, exhibiting in pin photodiode design dark current density values as low as 13nA.cm-2 at
-50mV and R0A product as high as 6x106 WΩcm2 at 77K. Then, a new unipolar nBn InSb/InAlSb/InSb detector structure on InSb substrate were designed in order to suppress generation-recombination dark
current. The first InSb nBn devices were fabricated and preliminary electrical characterizations are reported.
In this communication, the potentiality of InSb material as an avalanche photodiode (APD) device is
investigated. Current density-voltage (J-V) characteristics at 77K of InSb pin photodiodes were simulated by
using ATLAS software from SILVACO, in dark conditions and under illumination. In order to validate
parameter values used for the modeling, theoretical J-V results were compared with experimental
measurements performed on InSb diodes fabricated by molecular beam epitaxy. Next, assuming a
multiplication process only induced by the electrons (e-APD), different designs of separate absorption and
multiplication (SAM) APD structure were theoretically investigated and the first InSb SAM APD structure
with 1μm thick multiplication layer was then fabricated and characterized.