Preparation of cubic boron nitride thin film by the helicon wave plasma enhanced chemical vapor deposition

Abstract

Cubic boron nitride (c-BN) film was deposited on Si(100) substrate using the chemical vapor deposition process assisted by high density plasma of Helicon wave with Borazine (B3N3H6) precursor. It was found that the bombardment of ions with high flux and energy onto the film was necessarily required for synthesizing a c-BN film. Increasing a negative rf bias on the substrate increased the formation fraction of c-BN in the film. A nearly pure c-BN phase was synthesized at the conditions of plasma density in the reactor and rf substrate bias, above 10(11) cm(-3) and -350 V, respectively. The phase identification of BN film was carried out by the transmission electron microscopy as well as Fourier transformed infrared spectroscopy. The infrared spectra for c-BN film synthesized at the rf bias of -350 V appeared at 1093 cm(-1) with a strong single peak, which is close to a value for the characteristic vibration mode of bulk c-BN (1065 cm(-1)). The c-BN in the film was also confirmed and found to be a fine poly-crystalline with the grain sizes ranging from 200 to 400 Angstrom. (C) 1996 American Institute of Physics.