The 3C-SiC heteroepitaxial layers, voluntary doped with nitrogen, were grown by hot-wall chemical vapor deposition (CVD) on (111) and (10 0) oriented silicon substrates. The dependence of dopant incorporation on nitrogen flow rate, C/Si ratio, growth rate, growth temperature and reactor pressure has been investigated. The site competition between nitrogen and carbon and the doping efficiency in (111) and (10 0) oriented layers has been thoroughly studied. The reduction of the band gap energy as well as the modification of the infrared reflectivity has been observed at high doping level. Both effects confirm the substitutional character of nitrogen incorporation. Finally, a reduction of the tensile curvature of the wafer with increasing nitrogen doping has been stated. (C) 2008 Elsevier B.V. All rights reserved.