The effect of the deposition rate on the properties of d.c.-magnetron-sputtered niobium nitride thin films

The effects of the deposition rate on the properties of d.c.-magnetron-sputtered niobium nitride thin films are described. The films were deposited onto polished silicon and glass substrates which were maintained at room temperature. A study of the variation in the deposition rate, particularly through the target discharge current, total gas flow rates and total sputtering pressure was made to determine the optimum conditions for NbN film preparation. The transition temperature and the sheet resistance ratio increased monotonically with the deposition rate, and the transition temperature varied between 7.4 and 14.7 K. For a deposition rate of 9 Ås-1, a target discharge current of 1.8 A, 15% nitrogen and 85% argon and a total sputtering pressure of 0.88 Pa, the transition temperature was 14.7 K and the resistivity ratio was 0.90. In addition, the transition width of the films decreased with increasing deposition rate and reached a minimum of 0.20 K for the same conditions given above.