CUBIC BORON NITRIDE FILMS FROM A NOVEL NONEQUILIBRIUM PLASMA JET TECHNIQUE

CUBIC BORON NITRIDE (C-BN) FILMS ARE ATTRACTIVE FOR COATING WEAR PARTS BECAUSE OF THEIR HARDNESS AND OXIDATION RESISTANCE. ITS WIDE BANDGAP AND HIGH THERMAL CONDUCTIVITY MAKE C-BN USEFUL FOR ELECTRONICS APPLICAITONS. A TECHNIQUE OF DEPOSITING PHASE-PURE C-BN FILMS AT COMMERCIAL RATES IS NEEDED TO ADVANCE THE USE OF THIS MATERIAL. THE FEASIBILITY OF USING THE NOVEL NON-EQUILIBRIUM PLASMA JET (NEP), WHICH IS CAPABLE OF DEPOSITING UNIQUE MATERIALS AT HIGH RATES, FOR PRODUCING C-BN FILMS IS BEING DEMONSTRATED. FILMS ARE BEING PRODUCED FROM THE GLOW DISCHARGE ENHANCED REACTION OF A HALOBORON WITH AMMONIA. ONE REACTANT IS PASSED THROUGH A GLOW DISCHARGE AND THE DISCHARGE PRODUCTS EXPANDED THROUGH A SUPERSONIC NOZZLE WHERE, ON EXITING THE NOZZLE, THEY MIX WITH THE SECOND REACTANT. THE SUPERSONIC STREAM IMPACTS A TEMPERATURE-CONTROLLED SUBSTRATE ON WHICH THE BORON NITRIDE IS DEPOSITED. OPERATING PARAMETERS SUCH AS PRESSURE, DISCHARGE GAS COMPOSITION, POWER, AND SUBSTRATE TEMPERATURE AND ELECTRICAL BIAS ARE VARIED TO IDENTIFY CONDITIONS TO DEPOSIT C-BN.