Uniform Non-stoichiometric Titanium Nitride Thin Films for Improved Kinetic Inductance Detector Arrays

We describe the fabrication of homogeneous sub-stoichiometric titanium nitride films for microwave kinetic inductance detector (KID) arrays. Using a 6 ′ ′ sputtering target and a homogeneous nitrogen inlet, the variation of the critical temperature over a 2 ′ ′ wafer was reduced to < 25 %. Measurements of a 132-pixel KID arrays from these films reveal a sensitivity of 16 kHz/pW in the 100 GHz band, comparable to the best aluminum KIDs. We measured a noise equivalent power of NEP = 3.6 × 10 - 15 W/Hz 1 / 2 . Finally, we describe possible routes to further improve the performance of these TiN KID arrays.