N-TYPE HIGH-CONDUCTIVE EPITAXIAL DIAMOND FILM PREPARED BY GAS-SOURCE MOLECULAR-BEAM EPITAXY WITH METHANE AND TRI-N-BUTYLPHOSPHINE

An n-type phosphorous (P) doped epitaxial diamond film with high condu ctivity was grown on a C(001) substrate by gas source molecular beam e pitaxy using methane and tri-n-butylphosphine. The electrical conducti vity of the diamond film was measured to be 0.33 (Omega cm)(-1) at 23 degrees C with its activation energy to be 0.12 eV. The Hall measureme nts showed n-type conduction and a carrier concentration of 1.6 x 10(1 8) cm(-3) at 400 degrees C, which is comparable to the P concentration determined by secondary-ion-mass spectroscopy. These indicate the for mation of shallow P donors with high electrical activation efficiency. A p-n junction diode was fabricated by growing a P-doped epitaxial fi lm on a boron-doped C(001) substrate, which showed for the first time a rectification ratio of similar to 10 at 10 V. (C) 1997 American Inst itute of Physics.