Abstract
Background subtraction practice in X-ray reflectivity reciprocal space mapping (XRRSM) is described and compared to the traditional specular reflectivity. XRRSM allows determining a more precise contribution of background to the reflectivity signal which manifests itself in an improvement of the resolution of interference fringes. Data analysis and influence of background subtraction determined by two methods on the structural parameters of thin film are discussed using simulated X-ray reflectivity.