Physical Properties of CVD-Derived NbN Films

Due to lack of research in this area, only limited information on film properties-CVD growth conditions relationships is available. The highest reported for a CVD-de-rived NbN film is 15.7 K (Table 2-4) [76]. The dependence of phase development on substrate temperature and CI2 flow rate will next be discussed. The reaction of NbCls 

A similar pattern is observed for CVD-derived Nb-N films using NH3 as the N source gas. In this instance, a deposition temperature of 880 °C gives rise to mixed phase Nb2N + NbN development, while deposition temperatures 900°C give phase-pure NbN films [76]. 

The dependence of Cl2(g) flow rate upon Nb-N phase formation at a substrate temperature of 1 3.50°C has been described [78]. According to this experiment, as the CI2 flow rate was increased, niobium-rich phase development was observed as follows  

As the CI2 (g) flow employed in this approach reacts with Nb metal to form NbCl5(g), this behavior might also be considered as the effect of NbCl5(g) flow rate upon NbN formation. These observations are consistent with an increase in NbCl5(g) concentration giving Nb-rich compositions. 

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