Growth and characterization of high-k dielectrics for field effect devices

Zusammenfassung

As metal oxide semiconductor devices scale down, the power dissipation due to gate current leakage is pushing to replace the conventional poly-Si/SiO2/Si gate stack with new materials. The thorough study of the physical properties of these materials under different growth techniques is essential in order to choose the more suitable alternative. Among the materials with a high dielectric constant (high-k), HfO2 and Hf silicates are the most promising substitutes. This thesis is focused on the com position, morphology and optical properties of HfO2 films deposited by high pressure sputtering, as well as, on the kinetics of the growth process. Metal-oxide-semiconductor devices are fabricated to evaluate the electrical properties of the films. M easurements of the capacitance as a function of both voltage and frequency are performed to determine the interface trap density. Finally, state of the art transistors fabricated at Interuniversity Microelectronic Center IMEC (Leuven, Belgium) are st udied. The effect of hot carrier degradation on atomic layer deposited HfSiON/SiO2 gate stacks is studied by an improved charge pumping technique.