BORON DOPING OF DIAMOND FILMS BY B2O3 VAPORIZATION

Boron-doped semiconducting diamond films are deposited by hot-filament assisted CVD using boron trioxide (B2O3) as vaporization source. B2O3 is heated to different temperatures between 700 and 1000-degrees-C and the boron vapor is transported directly into the CVD reaction chamber. The resistivity of the B-doped films decreases with increasing boron source temperature and a minimum resistivity of 10(-2) OMEGA cm is obtained. This technique is of a nontoxic character and avoids any boron condensation during vapor transportation, resulting in a uniform depth profile of boron as indicated by SIMS. The structural properties of B-doped diamond films are characterized by SEM and Raman spectroscopy. A Schottky diode is fabricated on B-doped diamond film base and excellent rectifying characteristics are exhibited in the temperature range 300 to 600 K.