Quantitative interpretation of infrared absorption bands from hexagonal, cubic and mixed boron nitride films

A quantitative interpretation of the transverse optic (TO) mode absorption band areas of sp(2) and sp(3) bonded BN is presented, using complementary Fourier transform infrared (FTIR) spectroscopy and nuclear reaction analysis (NRA). In agreement with phase segregation and random bonding models, the number of oscillators was found to be limited by the less abundant component. The amount of oscillators were expressed in areal mass, because this representation depends neither on the number of bonds per atom nor on the material density. Calibration factors equal to 2.50 and 1.91 cm(-1) (mu g cm(-2))(-1) were derived for sp(2) and sp(3) bonded BN, respectively. From that, formulae for the sp3 bonded atomic and volume fractions were proposed. It must be emphasized that these calibration factors are only valid for BN films deposited on silicon under ion assistance at moderate temperatures and for transmission measurements at normal incidence. (C) 1998 Elsevier Science S.A. All rights reserved.