Plasma-enhanced chemical vapor deposition of phosphorus nitride thin films: Auger spectroscopy characterization

Abstract Thin films of phosphorus nitride have been deposited on InP at 270°C by the PECVD method using phosphorus trichloride and ammonia diluted in hydrogen. Observation by scanning electron microscopy shows a compact, homogeneous and smooth film with a well-defined interface. The films have been characterized by infrared and optical absorption. The optical band gap values for the best films are 5.5 and 5.7 eV before and after annealing in a 5% H 2 and 95% N 2 atmosphere. Two typical samples have been studied by Auger spectroscopy measurements. The spectra scanned after Ar + sputter etching show good homogeneity of the phosphorus nitride film bulk. The presence of chlorine in the interface layer was particularly evidenced in the case of interface oxidization. The bulk composition evaluated using the peak to background ratios allowed us to conclude that the film has a composition near P 3 N 5 .