Chemical Vapor Deposition of n-Type SiC Epitaxial Layers Using Phosphine and Nitrogen as the Precursors

Epitaxial growth of n-type SiC was carried out using PH3 and N-2 as the dopant precursors in a chemical vapor deposition system. Compared to nitrogen, phosphorous incorporation has a weaker dependence on the flow rate and has a limited site competition effect. Also, phosphorus incorporation for a given precursor flow decreases with temperature while that of nitrogen increases. It was also observed that phosphorous incorporation increases with decreasing C/Si when the ratio is between 0.8 and 3, which suggests phosphorous might incorporate into C site. Variable temperature Hall measurements were used to characterize the doped layers. Two donor levels at 82-83 meV and 105-114 meV for phosphorous in 6H-SiC, 52-53 meV and 78-80 meV for phosphorous in 4H-SiC were resolved. These results were compared to those from ion-implanted samples and nitrogen-doped samples.