Stoichiometric and non-stoichiometric films in the Si–O–N system: mechanical, electrical, and dielectric properties

Abstract

A novel low-temperature (600–850 °C), chemical vapor deposition method, involving a simple reaction between disiloxane (H 3Si–O–SiH 3) and ammonia (NH 3), is described to deposit stoichiometric, Si 2N 2O, and non-stoichiometric, SiO x N y , silicon oxynitride films (5–500 nm) on Si substrates. Note, the gaseous reactants are free from carbon and other undesirable contaminants. The deposition of Si 2N 2O on Si (with (1 0 0) orientation and a native oxide layer of 1 nm) was conducted at a pressure of 2 Torr and at extremely high rates of 20–30 nm min −1 with complete hydrogen elimination. The deposition rate of SiO x N y on highly-doped Si (with (1 1 1) orientation but without native oxide) at 10 −6 Torr was ∼1.5 nm min −1, and achieved via the reaction of disiloxane with N atoms, generated by an RF source in an MBE chamber. The phase, composition and structure of the oxynitride films were characterized by a variety of analytical techniques. The hardness of Si 2N 2O, and the capacitance–voltage ( C– V) as a function of frequency and leakage current density–voltage ( J L– V) characteristics were determined on MOS (Al/Si 2N 2O/SiO/ p-Si) structures. The hardness, frequency-dispersionless dielectric permittivity ( K), and J L at 6 V for a 20 nm Si 2N 2O film were determined to be 18 GPa, 6 and 0.05–0.1 nA cm −2, respectively.