Growth of Structured Non-crystalline Boron-Oxygen-Nitrogen Films and Measurement of Their Electrical Properties

The boron-oxygen-nitrogen (BON) films have been grown on Si wafer by the low-frequency rf-plasma-enhanced metal-organic chemical vapor deposition method. The homogeneous film structure of completely amorphous BON is first fabricated on a low-temperature-made buffer at 500°C with N₂ plasma and is observed with a high-resolution electron microscope by the transmission electron diffraction. The results show that the interfaces among substrate/buffer/film are clear and straight in the structured film. A heterogeneous film containing nano-sized crystalline particles is also grown by a routine growth procedure as a referential structure. The C-V characteristic is measured on both the amorphous and crystal-containing films by using the metal-oxide-semiconductor structure. The dielectric constants of the films are, therefore, deduced to be 5.9 and 10.5 for the amorphous and crystal-containing films, respectively. The C-V results also indicate that more trapped charges exist in the amorphous film. The binding energy of the B, O, and N atoms in the amorphous film is higher than that in the crystal-containing one, and the N-content in the latter is found to be higher than that in the former by x-ray photo-electron spectroscopy. The different electrical property of the films is thought to originate from the energy state of the covalent electrons.