Highly Thermal-Stable Amorphous TaSi2Cx Thin Films

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 at %) sustain amorphous phase at 800 oC for at least 30 minutes. 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 oC (x= 19 at%) or 800 oC (x= 22 at%) for at least 5 minutes without a sharp increase in sheet-resistance nor the formation of Cu3Si. Since Ta, Si and C are compatible with IC processing, these films are readily applicable as diffusion barriers in Cu metallization.