Low energy ion impact-enhanced growth of cubic boron nitride in a supersonic nitrogen/argon plasma flow
- Mechanical Engineering Department, Stanford University, Stanford, California 94305-3032 (United States)
This paper describes the growth and analysis of cubic boron nitride films in a low-density, supersonic nitrogen/argon plasma flow into which boron trichloride gas was injected. Both hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN) were synthesized using this apparatus. Phase selectivity is obtained by applying a relatively low negative bias voltage on the substrate. All of the films described in this paper were grown on {l_brace}100{r_brace} silicon wafers at substrate temperatures varying from 400{endash}700{degree}C. Boron nitride films with greater than 90{percent} cubic phase were successfully synthesized with this method. The films were analyzed using infrared spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. The volumetric percentages of the hexagonal and cubic phases were determined from model fits to the infrared transmission spectra of the films. X-ray photoelectron spectroscopy provided qualitative evidence for the presence and/or lack of sp{sup 2} bonding through the identification of a {pi}-plasmon feature in the spectra. Infrared reflectance spectra are used to provide insight into the growth mechanisms leading to c-BN formation and have revealed features which are not present in the transmission spectra, specifically the 1305cm{sup {minus}1} LO mode of c-BN and the 1610cm{sup {minus}1} LO mode of h-BN. The mean ion energies involved with this bias-enhanced chemical vapor deposition (CVD) process are much lower than the ion energies in traditional physical vapor deposition processes; however, the ion fluxes (currents) used in this CVD process are at least an order of magnitude higher, resulting in a total momentum transfer to the deposited atoms through ion bombardment that is at least equal to or greater than that reported for many ion-enhanced PVD processes. {copyright} {ital 1997 Materials Research Society.}
- OSTI ID:
- 542185
- Journal Information:
- Journal of Materials Research, Vol. 12, Issue 8; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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