Low resistivity p+ diamond (100) films fabricated by hot-filament chemical vapor deposition

Abstract

By hot-filament (HF) chemical vapor deposition (CVD), heavily boron (B)-doped single-crystal diamond (100) films were fabricated and their structural and electrical properties were studied. We did not observe the soot formation, which is frequently observed and limits the performances in the case of microwave plasma (MWP) CVD. The B concentration was successfully controlled over the range from 1019 to 1021cm−3. Hillock-free films were obtained, whose mean surface roughness measured by atomic force microscopy (AFM) was less than 0.1nm. From the reciprocal space mapping (RSM) around 113 diamond reflection, it was revealed that the films possess the smaller lattice expansion than that expected from the Vegard's law. The room-temperature resistivity was decreased lower than 1mΩ·cm for B concentration ~1021cm−3. These results indicate that the HFCVD possesses large potential for fabricating the device-grade p+ diamond.