Electronic transport in heavily Si doped cubic boron nitride films epitaxially grown on diamond(001)

Structural phase analysis and measurements of electronic transport properties were carried out on heavily Si-implanted cubic (c-) BN films heteroepitaxially grown on diamond(001). Pure cubic phase can be conserved after Si implantation up to a concentration of 2x10(20) cm(-3) and a related implantation damage of 0.9 displacements per atom. As a result, the temperature dependent sheet resistance is lowered by seven orders of magnitude as compared to undoped films. By temperature dependent Hall effect measurements, n-type conduction is confirmed for these heavily Si-implanted c-BN films. Due to the high Si doping levels a semiconductor-to-metal transition is approached as signaled by the extremely small activation energies of typically 0.05 eV as well as by an almost temperature independent negative carrier concentration up to 470 K. At higher temperatures an additional activated process sets in resulting in a further increase in carrier concentration with an activation energy of 0.4 eV. (c) 2008 American Institute of Physics.