[23p-D214-1~19] 11.5 Junction and circuit fabrication process, digital applications

▲ [23p-D214-12] Cryogenic NbTiN Thin Film Resistors for Superconducting MMICs Fabricated by Using Reactive Magnetron Sputtering

〇Wenlei Shan¹, Shohei Ezaki¹ (1.NAOJ)

Keywords:NbTiN Thin film, Reactive Magnetron Sputtering, Superconducting MMIC

Reactive magnetron sputtering has been applied for fabrication of NbTiN thin film resistors operating at liquid helium temperature. The resistivity of the NbTiN films at 4K can be tuned in a wide range from about 100 μΩcm to 10, 000 μΩcm with sputtering parameters such as discharge current and sputtering pressure. This broad tuning range greatly facilitates the design and fabrication of on-chip lumped-element resistors for millimeter and submillimeter integrated circuits. The NbTiN thin film resistors are found to be nitrogen-deficient, and the resistivity is strongly dependent on the nitrogen atom ratio. A numerical model of reactive magnetron discharge has been utilized to understand the tuning mechanism. The details of this method have been presented in the 68^th JSAP Spring Meeting however without providing sufficient experimental proofs. In this study, we applied the theory to reproduce the experimental results, and verified that the simulation results qualitatively meet well with the measured ones.