Method to Fabricate Low Stress Refractory Metal Silicide Films
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Polycide and self-aligned silicide technologies have experienced problems such as adhesion loss, silicide "sag", and increased "bird's beak" due to high post-anneal silicide film stress. The high film stress results from the difference between the thermal expansion coefficients of the silicide film and substrate. Limited oxygen incorporation into a silicide film reduces post-anneal film stress while causing only a slight increase in film resistivity. Oxygen is purposely incorporated into the silicide film during deposition. The figure shows post-anneal film stress (1000 degrees C, 30 minutes, N2) and resistivity as a function of percentage of oxygen in the sputtering gas (oxygen/argon mixture) for titanium silicide (TiSix) films. For microelectronic applications, the optimum oxygen content for TiSi1.