Synthesis of adhesive c-BN films in pure nitrogen radio-frequency plasma

Cubic boron nitride (c-BN) thin films were prepared at 600 degrees C by rad io-frequency (rf) plasma pulsed laser deposition. All c-BN films prepared i n Ar-rich plasma have poor adhesion on Si(100) substrates, but those prepar ed in pure N-2 plasma can be maintained for more than 5 months without degr adation. However, an increase of ion flux at an ion energy similar to that of pure N-2 plasma results in the peeling of c-BN films. Thus, application of pure N-2 plasma with suppressed ion flux can improve c-BN film adhesion. Under such conditions, an extended sp(2)-bonded interlayer is suspected, w ith the onset of the c-BN phase being delayed. Suppression of radiative dam age in reduced nitrogen ion flux on both the c-BN and h-BN/t-BN phases are important for the adhesive of c-BN films. (C) 1999 Elsevier Science S.A. Al l rights reserved.