S. Muhl1, S. E. Rodil1, L. E. Sanchez-Balanzar1 and E. Camps2
1) Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510, México. 2) Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, México DF 11801, México.
In a sputtering system the optimal strength of the magnetic field of the magnetron depends on a combination of the sheath width and target voltage. When RF or pulsed DC (P-DC) are used the overvoltage associated with restarting the plasma in each cycle, plus the varying voltage means that the magnetron might not be effective. To study this, we prepared carbon and titanium thin films by magnetron sputtering, with and without the magnets, using DC, RF or 250 kHz P-DC. Without the magnets the useable plasma power was less than 80 W for RF and 200 W for P-DC, using the graphite target, and 300 W RF and 200 W P-DC using the titanium target. The deposition rates without the magnets were reduced by about half, independent of the target or type of high frequency excitation, and the DC deposition rates were 2 to 3 times the high-frequency rates.