Low resistivity Ta textured film formed on TaN

Ta films formed on Si(100) and quartz substrates by sputtering technique usually lead to a textured β-Ta with tetragonal crystal lattice. The β-Ta film has a high resistivity. As a comparison, low resistivity α-Ta with cubic crystal lattice can be formed by sputtering on TaN. Crystal study shows that the sputtered TaN film has a preferred (111) growth plane and the α-Ta has a preferred (110) growth plane. Both are textured films. The growth mechanism of the α-Ta on TaN is ascribed to epitaxy.