Deposition of Cubic Boron Nitride in a Supersonic Plasma Jet Reactor with Secondary Discharge

Abstract

We have deposited cubic boron nitride thin films with a supersonic plasma jet chemical vapor deposition system with bipolar pulsed substrate bias. Deposited films were characterized by Fourier transform infrared spectroscopy, micro-X-ray diffraction, and scanning electron microscopy. The cubic boron nitride content is observed to scale well with the degree of ion bombardment of the substrate and growing film, which is affected most drastically by the substrate bias pulse frequency, and positive and negative duty cycle. The magnitude of the negative substrate bias was also critical in depositing cubic boron nitride, with a threshold voltage of approximately 90 V necessary for cubic boron nitride deposition.