The disclosure is directed to nondestructive systems and methods for simultaneously measuring active carrier concentration and thickness of one or more doped semiconductor layers. Reflectance signals may be defined as functions of active carrier concentration and thickness varying over different wavelengths and over different incidence angles of analyzing illumination reflected off the surface of an analyzed sample. Systems and methods are provided for collecting a plurality of reflectance signals having either different wavelengths or different incidence angle ranges to extract active carrier density and thickness of one or more doped semiconductor layers.