PROCESS DIAGNOSTICS DURING THE DEPOSITION OF CUBIC BORON-NITRIDE

Using spatially resolved optical emission spectroscopy and Langmuir do uble probe technique, the magnetron deposition process of cubic boron nitride thin films has been investigated. The ion current to the r.f.- biased substrate electrode was estimated by means of Bohm's sheath cri terion. In order to deposit the cubic boron nitride phase, a much high er ion energy is required in the d.c. magnetron in comparison to the r .f. sputtering magnetron mode at usually applied target power. Further more, there is a significant phase inhomogeneity across the substrate holder. Both facts have been explained in terms of the total momentum per deposited boron atom. The plasma excitation degree (vibrational an d excitation temperatures) determined by emission spectroscopy was fou nd to be higher in the r.f. sputtering mode. It has been shown that bo th in situ techniques applied can supply reliable information on the r eactive magnetron deposition process. (C) 1997 Elsevier Science S.A.