The features of transient processes under the field effect in PbSnTe:In films with a variation in the current up to a factor of 105 are studied at helium temperatures. These features qualitatively correspond to a model, in which a high concentration of traps with different parameters is present on the PbSnTe:In surface. The role of the surface is confirmed by a strong variation in the experimental characteristic after the chemical removal of native oxides from the PbSnTe:In surface and its passivation by an Al2O3 layer.