Synthesis of stoichiometric zirconium nitride by d.c. reactive magnetron sputtering pulsed at low frequency: characterization by ESCA, SIMS and electron microprobe

In order to raise the deposition rate of ZrN during its synthesis by d.c. r eactive magnetron sputtering, we have applied a technique of pulsed dischar ge current. Zirconium nitride has been deposited in the transition between the metallic and the compound sputtering regime. This transition appears be tween 1 and 10% of N-2 in the Ar/N-2 gas discharge mixtures. The discharge current has been modulated by a square wave at four frequenci es of 5, 2.5, 1.25 and 0.83 Hz, A bias of -200 V was applied to the substra te. The final thickness of the films in each experiment was similar to 300 nm, The films have been analysed by electron microprobe, by SEM for cross-s ection view and by ESCA and SIMS for depth profiles. It can be concluded that: the deposition rate is enhanced by a factor that seems to depend essentially on the additional power brought by the modulati on, and not on the frequency; the films are very compact without any column ar structure; the films are stoichiometric in all the domain of nitrogen co ncentration examined tin non-pulsing regime, stoichiometric films can be ob tained only in a very narrow domain of concentration); and the depth profil es obtained hy ESCA and SIMS prove that the films are very homogeneous and that oxygen is only present in a surface oxide layer (2-5 mn), Copyright (C ) 2000 John Wiley & Sons, Ltd.