We present a study of thin-film molybdenum resistors for NbN electronics operating at cryogenic temperatures. The key step is the 0.5-1.5 keV ion cleaning-activation of NbN before Mo deposition which allows to obtain a high-quality Mo/NbN interface which together with additional aluminum bandage layer in the area of contact pads allow to reduce contact resistance below 1 Ohm. The quality of the interfaces is confirmed by transmission electron microscopy and X-ray reflectometry.
