Characterization of free-standing single-crystal diamond prepared by hot-filament chemical vapor deposition

• Free-standing single-crystal diamond plates were prepared by HFCVD.
• Growth rate was 1.7 μm/h at 3% methane concentration in 30 Torr atmosphere.
• A tungsten impurity level of 1018 cm− 3 from filaments was detected by SIMS.
• Non-epitaxial crystallites could be suppressed by using off-axis angle above 3°.
• HFCVD-grown plates have good crystalline quality comparable to the seed substrates.

Hot filament chemical vapor deposition (HFCVD) possesses a large potential to scale-up for the growth of single-crystal diamond (SCD). This study investigates the crystalline qualities of SCD fabricated by HFCVD. A tungsten impurity level of 1018 cm− 3 was detected with secondary ion mass spectroscopy. The full-width at half maximum (FWHM) of the rocking curve (004) was 39.5 arcsec, where that of seed substrates was 42.8 arcsec. A clear free-exciton recombination radiation was observed in cathodoluminescence spectra. The Raman spectra presented a single peak centered at 1333.2 cm− 1 with a FWHM value of 1.9 cm− 1. These results indicate that the HFCVD-grown SCD has good crystalline quality comparable to the seed substrates.