Phenomenes de transport dans un dispositif microelectronique modifie par laser (French text)

A simple theoretical model is developed to express with a current density versus voltage relation the transport behaviour of laser-diffused resistors. This model is successfully applied to experimental data and its limits are tested with numerical simulations. A space-charge-controlled current injection model dominated by charge carriers' velocity saturation gives us the possibility to compare and describe devices according to their saturation field and average impurities' concentration. The values obtained by curve fitting of the model confirm the application of Ohm's law to small electric fields. This study shows the possibility of the presence of structural defects for low resistance (around 500 Ω) and small gap length (0.6 μm) devices. A better understanding of the transport mechanisms is reached.; The temperature variation of the transport behaviour is also studied. Many different behaviours are observed and characterized as a function of the fabrication processes: a metallic and a semiconductor behaviour are observed as a function of the average impurities concentration (between 1016 cm−3 and 1019 cm−3 ). A model for the engineering of the temperature coefficients of variation is also introduced for the devices presenting a metallic behaviour.; Finally, a transient analysis of the current in the devices under a voltage step function gives the possibility to study the response time of laser-diffused resistors. A simple electrical model based on the presence of carriers' traps is then introduced to explain the observed phenomena. The electrical model, composed of a perfect resistor in parallel with a capacitor, gives a good explanation of the transient phenomena observed. The electrical model is also supported by numerical simulations.