Niobium nitride (NbN) thin films are of considerable interest due to their excellent mechanical and chemical stability, as well as having useful superconducting properties. Regarding the latter, NbN has a relatively high critical temperature (T c ), critical field (H c2 ), and critical current density (J c ), and has a refractory nature. It is therefore a promising candidate for superconducting microelectronics applications such as superconducting quantum interference devices (SQUIDs), radio frequency (rf) filters, antennae, and sensitive infrared (IR) sensors. [1±4] Thus far, NbN thin films have been grown primarily by physical vapor deposition (PVD) techniques, including sputtering, [5±8] pulsed laser deposition (PLD), and molecular beam epitaxy (MBE). Among these, reactive sputtering has been most frequently employed, and NbN thin films with T c values approaching 16 K have been grown by optimized reactive sputtering. However, superconducting NbN film growth mechanisms have not been fully elucidated; moreover, optimal growth conditions are highly growth system specific, and the growth reproducibility of high-quality films is not yet satisfactory.
CVD is a widely utilized technique in film growth research as well as in industrial-scale production. Although the attractions of CVD include excellent step coverage, adaptability to large-scale growth processes, and relatively simple apparatus, relatively little work has been carried out on NbN x thin films. Understanding and perfecting NbN CVD processes would better define the parameters required for large-scale NbN CVD, as well as for nitride CVD in general. Additional knowledge would also lead to Communications