THRESHOLDS FOR THE PHASE-FORMATION OF CUBIC BORON-NITRIDE THIN-FILMS

We introduce a phase diagram for boron nitride film growth. It is base d on studies of the influence of the ion energy and substrate temperat ure on the phase formation using mass-selected ion-beam deposition of Bt and N+ ions. For the formation of the cubic phase we find threshold values of 125 eV for the ion energy and 150 degrees C for the substra te temperature. Furthermore, we find a characteristic ion energy and s ubstrate temperature dependence of the compressive stress, yielding lo w stress values for high energies and/or temperatures. c-BN nucleation and growth is attributed to a subsurface process qualitatively descri bed by the subplantation model.