Abstract : Design and fabrication of a thermal platform for microfluidics applications The concept of lab on chip was created in the beginning of 90. In our case, for chemical applications in microfluidic environment, the temperature control is the first physical phenomenon to be studied. Thermal actuators are encountered in several microsystems applications as hot plates for gas sensors, thermo-mechanic actuators for optical switching, igniters for microthusters, or heaters for droplet ejectors. We present in this thesis a generic approach for the development of polysilicon diodes for thermal sensing and control applications in microfluidic environment.We propose a simple and reliable technology based on symmetrical polysilicon diodes (Zener effect) that can be implemented either on silicon, glass or silicon carbide substrates. We have a dual device which can be used both for thermal sensing and actuating applications. Electrical characterization show thermal sensitivities from 220 to 22 mV/°C, thats depend on geometrical and technological parameters. The capacity to measure temperature in microfluidic environment was demonstrated for different substrates. Last part of this work concerns the development of an instrumentation platform linked to a computer that allows a simple determination of the detected temperature from current measurement.