Effect of magnetic field configuration on the properties of thin films sputter deposited from a dc magnetron TiNi target

Abstract

A direct current magnetron target assembly with rotating adjustable magnets arrangement has been used for thin film sputter deposition from a 200 mm diameter TiNi target in a PE 4450 sputtering system. It was found that for a simple circular magnet arrangement placed 20 mm off the rotation axis the films deposited on the stationary pallet have significant variation in M s temperatures as measured from the center of the magnetron. This variation across the 100 mm wafer is as large as -100°C. The gradient in M s for the sputtered film can be significantly lowered by using an appropriate configuration of magnets, which in combination with rotation of the pallet, results in narrowing the difference in M s to less than 10°C. Further adjustment of transformation temperatures of the film can be accomplished by simultaneous sputtering on the rotating pallet from two targets. Depending on which direction the transformation intervals need to be moved, the second target should be either Ti or Ni. The deposition rates for the TiNi and Ni targets were calibrated and calibration results were applied for calculating the power settings to sputter film with A f = ∼15°C. The transformation intervals and stress-strain curves across a 100 mm wide area were measured for this film.