Stable temperature coefficient of resistance in TiSiON thin film resistors deposited by magnetron co-sputtering

• Amorphous TiSiON thin films achieved by magnetron co-sputtering.
• Oxygen addition increases sheet resistance and enables close to zero temperature coefficient of resistance.
• Nitrogen addition improves film stability and yields closer to zero temperature coefficient of resistance.

Thin films of titanium/silicon (Ti:Si) are widely employed in the electronics industry because of their metal-like characteristics. The use of films as thin film resistor (TFR) based on Ti:Si has not yet been reported. In this paper, the TFR characteristics of TiSiON with different compositions and deposited in Argon atmosphere with either 1% Oxygen or 1% Oxygen/3% Nitrogen are studied. The film composition was varied through a co-sputtering approach from titanium and silicon targets and the sheet resistance (Rsh) and temperature coefficient of resistance (TCR) were evaluated. The film composition was evaluated by X-ray photoelectron spectroscopy (XPS); carrier mobility, type and concentration by Hall effect methods and film microstructure by X-Ray diffraction. Nitrogen addition during the deposition reduces oxidized species in the TFR and increases film stability. The addition of nitrogen results in TFR films with partially oxidized titanium and silicon and TFR values closer to zero TCR without impacting film resistance. Films deposited without nitrogen result in more unstable films and larger TCR. A near-zero TCR film was found for a Ti:Si ratio of 1.6, exhibiting a Rsh at 25 °C of 0.7 kOhms with a TCR value of −171 ppm/°C after annealing at 450 °C in forming gas.