Enhancement of phosphorus incorporation and growth rate of epitaxial diamond films by the addition of nitrogen

摘要

The influence of the addition of nitrogen on the phosphorus incorporation into and the growth rate of epitaxial diamond films grown by hot filament chemical vapor deposition, using a solid compound (NH_4H_2PO_4) as a doping source, was investigated. Experiments show that the introduction of nitrogen gas into the system increases both the segregation of phosphorus in the epitaxial diamond and the film growth rate. The enhancement of phosphorus incorporation was attributed to the local lattice dilatation caused by a significant level of nitrogen dopant, while the increase of growth rate was explained by a model for defect-induced stabilization of diamond. From the secondary ion mass spectrometry analysis, it was found that the effective incorporation efficiency of nitrogen in diamond is about 9 x 10~(-4). For phosphorus it can reach a value as high as approximately 1 x 10~(-3) when a large amount of nitrogen is introduced simultaneously to the system.