During the last years epitaxially grown periodic structures have attracted increasing interest in many fields of physics and device applications. As a consequence, the growth procedures tend towards complexity and an enhanced number of parameters has to be optimized. In situ growth control and analysis have been established as standard procedures yielding parameters like growth rate, layer composition and crystalline quality and, thus are directly affected by the increasing complexity of the grown structures. In this paper we focus on the MOVPE and in situ investigation of periodic III-nitride heterostructures and delta-doped layers using laser reflectometry and X-ray diffraction. It is demonstrated that essential structural parameters of periodic structures as periodicity, layer thickness, growth rate and layer composition can be deduced by in situ characterization techniques yielding additional and consistent information about the deposited III-nitride structures in comparison with ex situ analysis. (C) 2007 Elsevier B.V. All rights reserved.