Cu-Doped TiN_xO_y Thin Film Resistors DC/RF Performance and Reliability

Featured Application High-frequency integrated circuits, heterogeneously integrated and hybrid RF circuits. We fabricated Cu-doped TiNxOy thin film resistors by using atomic layer deposition, optical lithography, dry etching, Ti/Cu/Ti/Au e-beam evaporation and lift-off processes. The results of the measurements of the resistance temperature dependence, non-linearity, S-parameters at 0.01-26 GHz and details of the breakdown mechanism under high-voltage stress are reported. The devices' sheet resistance is 220 +/- 8 Omega/ (480 +/- 20 mu Omega*cm); intrinsic resistance temperature coefficient (TCR) is similar to 400 ppm/degrees C in the T-range of 10-300 K; and S-parameters versus frequency are flat up to 2 GHz with maximum variation of 10% at 26 GHz. The resistors can sustain power and current densities up to similar to 5 kW*cm(-2) and similar to 2 MA*cm(-2), above which they switch to high-resistance state with the sheet resistance equal to similar to 200 k Omega/ (similar to 0.4 Omega*cm) caused by nitrogen and copper desorption from TiNxOy film. The Cu/Ti/TiNxOy contact is prone to ageing due to gradual titanium oxidation while the TiNxOy resistor body is stable. The resistors have strong potential for applications in high-frequency integrated and hybrid circuits that require small-footprint, medium-range resistors of 0.05-10 k Omega, with small TCR and high-power handling capability.