Growth of boron-doped diamond seed crystals by vapor deposition

Abstract

p‐type semiconducting diamond was grown by vapor deposition from a 0.83% diborane in methane gas mixture at 1050°C and 0.2 Torr on 0 to 1‐μ nominal size natural type‐I diamond powder. Total mass increases of about 9% were achieved which correspond to average linear growth rates of less than 10⁻³ μ/day. Evidence showing the growth was boron‐doped diamond included chemical etching, x‐ray and electron diffraction, density measurements, Seebeck and resistivity measurements, chemical analysis, optical measurements, induced electron emission spectroscopy, and scanning electron microscopy. The crystalline quality of the new diamond has not been established; it may be highly defective. A distinct change in color of the diamond seed crystals from an off‐white or gray for virgin crystals to light blue after growth was observed. The results are further confirmation that diamond may be grown at low pressures where it is thermodynamically metastable with respect to graphite. It is also further evidence that boron is the element responsible for blue p‐type diamonds.