Using the method of ion-assisted plasma deposition under conditions of reduced-bias growth, we have been able to achieve thick coatings of cubic boron nitride on silicon. A key aspect of our technique is to monitor the accumulation of compressive stress in the film and to reduce its effects by appropriate choice of deposition parameters and strain-relieving buffer layers. For this purpose, we employ a battery of real-time in situ characterization tools, which are capable of accurately tracking important film growth parameters, such as nucleation density, surface roughness, crystallographic structure and texture, and residual film stress. We use a combination of electron (reflection high-energy electron diffraction, RHEED) and laser beam (multi-beam optical stress sensor, MOSS) probes to provide this information during growth. Our results demonstrate that we can successfully produce superhard cubic boron nitride coatings up to 2 mum in thickness.