Highly Thermal-Stable Amorphous TaSi[sub 2]C[sub x] Films as Diffusion Barrier

Structural changes at high temperature of amorphous TaSi2Cx films deposited on Si(100) were evaluated. Increased carbon content remarkably raises crystallization temperature; thus, TaSi2Cx films (x > 16 atom %) sustain amorphous phase at 800 degrees C for at least 30 min. A preliminary evaluation of such films as a diffusion barrier of Cu metallization in a sandwich scheme Si (100)/TaSi2Cx (20 nm)/Cu showed the stability of 750 degrees C (x = 19 atom %) or 800 degrees C (x = 22 atom %) for at least 5 min without a sharp increase in sheet resistance nor the formation of Cu3Si. Because Ta, Si, and C are compatible with integrated-circuit processing, these films are readily applicable as diffusion barriers in Cu metallization. (c) 2007 The Electrochemical Society.