Oral Presentation

4K Cryogenic Nitrogen-deficient NbTiN Thin Film Resistors Fabricated by Using Reactive Sputtering

Author(s): Wenlei Shan, Akihira Miyachi, Shohei Ezaki, and Kazumasa Makise (NAOJ)

Presenter: Shan Wenlei (National Astronomical Observatory of Japan)

A reactive sputtering process has been applied for fabrication of NbTiN thin film resistors operating at liquid helium temperature. The resistivity of the NbTiN films at 4 K can be tuned in a wide range around 800 uOhm-cm by tuning sputtering parameters such as discharge current and total sputtering pressure. The achieved high resistivity enables on-chip lumped element resistors for millimeter and submillimeter integrated circuits. The NbTiN thin films are deficient in nitrogen with atomic ratio being about 0.3 measured with EDS (energy dispersive X-ray spectroscopy). A numerical model of the reactive magnetron discharge has been developed to understand the tuning mechanism, and the theoretical results qualitatively meet the measured ones.