A method of fabricating an integrated circuit includes forming a titanium nitride layer over a semiconductor substrate in a process chamber and forming a poisoned titanium layer on the titanium nitride layer in the process chamber. Forming the titanium nitride layer includes sputtering titanium from a titanium sputter target using a first nitrogen flow. Forming the poisoned titanium layer includes sputtering titanium from the titanium sputter target using a lower second nitrogen flow. The method also forms an aluminum layer on the poisoned titanium layer.