The purpose of this paper is the study of the impact ionization and the Auger recombination in Hg
1-xCd
xTe avalanche photodiodes, with

. For

it is shown that the spin orbit splitting Δ is lower than the bandgap energy E
gso that impact ionization is initiated by holes from the Split-off valence band. For

, the rate of the Auger recombination is maximum, corresponding to a resonant impact ionization and to a maximum ratio

where α and β are, respectively, the impact ionization coefficient for electrons and holes.