Boron nitride thin films were synthesized on Silicon and quartz substrates by low pressure chemical vapor deposition using triethylamine-borane complex and ammonia as precursors. The films were processed at 550°C, 575°C and 600°C at a constant pressure of 0.05 Torr at different precursor flow rates and flow ratios.
Several analytical methods such as Fourier transform infrared spectroscopy, x- ray photo-electron spectroscopy, ultra-violet/visible spectrophotornetry, ellipsometry, surface profilometry and scanning electron microscopy were used to study the deposited films. The films deposited were uniform, amorphous and the composition of the films varied with deposition temperature and precursor flow ratios. The stresses in the film were either mildly tensile or compressive.
Dielectric constant characterization of LPCVD boron nitride was made using metal-insulator-semiconductor (MIS) and metal-insulator-metal (M IM) structures. The boron nitride films were stable and showed dielectric constant values between 3.8 and 4.7. The limitation of attaining lower values could be due to the presence of carbon as an impurity in the film and the presence of mobile charge carriers in the films as well as at the substrate-film interface.
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