Properly managing heat transfer is an issue of interest for various fields, for instance for miniaturized integrated circuits. Understanding the mechanisms of heat conduction in these systems requires in particular the investigation of the underlying physical mechanisms as a function of temperature and doping. In this work, we study the temperature dependence of silicon (Si) thermal conductivity as a function of doping for a large range of p and n concentrations. Planar Si substrates covered with a silicon dioxide layer 200 nm thick are characterized at cryogenic temperatures by means of the 3 omega method. The study is made for temperatures ranging from 78 K to 303 K. Particular attention is paid to the width of the linear metallic heater. The thermal conductivity of Si samples is determined by comparing experimental data to semi-analytical computations. Obtained values of lattice thermal conductivity are compared with analytical models based on the Boltzmann transport equation (BTE) and other published modelling and experimental results. The characteristic doping concentration at which thermal conductivity reduces is especially underlined.