Chromium nitride films have been developed as an ‘industry
standard’ coating for tribological or decorative applications [1–3]. For
reactively sputtered films the predominant structure that forms
depends on a number of deposition parameters, which control the
energy delivered to the growing film. This includes the bias applied to
the substrate, both in terms of its magnitude and the mode in which it is
delivered (i.e. RF, DC, pulsed DC, etc.). In this study the system has been
characterised to identify the optimum conditions for CrN deposition,
then the effect of pulsing the substrate bias in the mid-frequency range
(100–350 kHz) during both the ion etching and deposition stages has
been investigated. Previous studies have shown that this can signifi-
cantly increase the ion current drawn at the substrate, possibly due to
the initiation of a second plasma discharge [4] in front of the substrate
compared to DC biasing and thereby provide enhanced deposition
conditions [5–7]. The earlier studies utilised pulsed biasing during the
deposition of TiO2 and TiN coatings. This is the first study in which this
technique has been applied to CrN films and builds upon earlier
published work [8] into the effects of ion energy and nitrogen content.