Cubic boron nitride thin films by tuned rf magnetron sputtering

Cubic boron nitride (c-BN) thin films were deposited on silicon by tuned substrate r.f. magnetron sputtering. A total gas flow of 3 sccm (90% Ar and 10% N-2) was introduced in a vacuum chamber at a pressure of 1 x 10(-3) Torr. Films were deposited at two r.f. target powers (360 and 500 W) developing d.c. potentials of - 220 and - 350 V respectively. The substrate holder, heated to 350 degrees C, was biased from - 40 to - 95 V and its influence on the cubic content in the films was studied. The c-BN percentage in the films was between 20 and 90%, as calculated by FTIR measurements. The stress effects were also analyzed by SEM. The grain sizes of the c-BN and h-BN crystals, measured by TEM, were about 30 and 20 nm, respectively. (C) 1997 Elsevier Science S.A.