Journal of Electronic Materials

, Volume 37, Issue 9, pp 1303-1310

First online:

Latest Developments of HgCdTe e-APDs at CEA LETI-Minatec

  • Johan RothmanAffiliated withCEA/LETI/DOPT Email author 
  • , Gwladys PerraisAffiliated withCEA/LETI/DOPT
  • , Philippe BalletAffiliated withCEA/LETI/DOPT
  • , L. MollardAffiliated withCEA/LETI/DOPT
  • , S. GoutAffiliated withCEA/LETI/DOPT
  • , J.-P. ChamonalAffiliated withCEA/LETI/DOPT

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In this communication, we report on the electro-optical characterization of planar back-side-illuminated HgCdTe electron initiated avalanche photodiode (e-APD) test arrays with cut-off wavelengths λ c = 2.4 μm, λ c = 4.8 μm, and λ c = 9.2 μm. The e-APDs were manufactured at LETI using absorption layers grown by molecular beam epitaxy (MBE). We present measurements of the distributions in gain, noise, and equivalent input dark current. The mid-wave (MW) diodes yielded a very low dispersion (2%) and high operability (98%) for gains up to M = 200. The excess noise factor and equivalent input current (I eq_in) operability were slightly lower, due to defects in the depletion region. The lowest measured value of I eq_in = 1 fA corresponds to the lowest level measured so far in HgCdTe e-APDs and opens the way to new applications. The gain in the long-wave (LW) diodes was limited by tunnelling currents to a value of M = 2.4, associated with an average noise factor F = 1.2. A gain of M = 20 at a bias of −22.5 V was demonstrated in the short-wave (SW) e-APDs.


HgCdTe APD MBE SW MW LW gain dispersion sensitivity